With the rapid development of the Internet of Things,there is a great demand for portable gas sensors.Metal oxide semiconductors(MOS)are one of the most traditional and well-studied gas sensing materials and have been...With the rapid development of the Internet of Things,there is a great demand for portable gas sensors.Metal oxide semiconductors(MOS)are one of the most traditional and well-studied gas sensing materials and have been widely used to prepare various commercial gas sensors.However,it is limited by high operating temperature.The current research works are directed towards fabricating high-performance flexible room-temperature(FRT)gas sensors,which are effective in simplifying the structure of MOS-based sensors,reducing power consumption,and expanding the application of portable devices.This article presents the recent research progress of MOS-based FRT gas sensors in terms of sensing mechanism,performance,flexibility characteristics,and applications.This review comprehensively summarizes and discusses five types of MOS-based FRT gas sensors,including pristine MOS,noble metal nanoparticles modified MOS,organic polymers modified MOS,carbon-based materials(carbon nanotubes and graphene derivatives)modified MOS,and two-dimensional transition metal dichalcogenides materials modified MOS.The effect of light-illuminated to improve gas sensing performance is further discussed.Furthermore,the applications and future perspectives of FRT gas sensors are also discussed.展开更多
As a kind of valuable chemicals,hydrogen peroxide(H2O2)has aroused growing attention in many fields.However,H2O2 production via traditional anthraquinone process suffers from challenges of large energy consumption and...As a kind of valuable chemicals,hydrogen peroxide(H2O2)has aroused growing attention in many fields.However,H2O2 production via traditional anthraquinone process suffers from challenges of large energy consumption and heavy carbon footprint.Alternatively,photoelectrocatalytic(PEC)production of H2O2 has shown great promises to make H2O2 a renewable fuel to store solar energy.Transition‐metal‐oxide(TMO)semiconductor based photoelectrocatalysts are among the most promising candidates for PEC H2O2 production.In this work,the fundamentals of H2O2 synthesis through PEC process are briefly introduced,followed by the state‐of‐the‐art of TMO semiconductor based photoelectrocatalysts for PEC production H2O2.Then,the progress on H2O2 fuel cells from on‐site PEC production is presented.Furthermore,the challenges and future perspectives of PEC H2O2 production are discussed.This review aims to provide inspiration for the PEC production of H2O2 as a renewable solar fuel.展开更多
Since the first report of amorphous In–Ga–Zn–O based thin film transistors,interest in oxide semiconductors has grown.They offer high mobility,low off-current,low process temperature,and wide flexibility for compos...Since the first report of amorphous In–Ga–Zn–O based thin film transistors,interest in oxide semiconductors has grown.They offer high mobility,low off-current,low process temperature,and wide flexibility for compositions and processes.Unfortunately,depositing oxide semiconductors using conventional processes like physical vapor deposition leads to problematic issues,especially for high-resolution displays and highly integrated memory devices.Conventional approaches have limited process flexibility and poor conformality on structured surfaces.Atomic layer deposition(ALD)is an advanced technique which can provide conformal,thickness-controlled,and high-quality thin film deposition.Accordingly,studies on ALD based oxide semiconductors have dramatically increased recently.Even so,the relationships between the film properties of ALD-oxide semiconductors and the main variables associated with deposition are still poorly understood,as are many issues related to applications.In this review,to introduce ALD-oxide semiconductors,we provide:(a)a brief summary of the history and importance of ALD-based oxide semiconductors in industry,(b)a discussion of the benefits of ALD for oxide semiconductor deposition(in-situ composition control in vertical distribution/vertical structure engineering/chemical reaction and film properties/insulator and interface engineering),and(c)an explanation of the challenging issues of scaling oxide semiconductors and ALD for industrial applications.This review provides valuable perspectives for researchers who have interest in semiconductor materials and electronic device applications,and the reasons ALD is important to applications of oxide semiconductors.展开更多
Metal oxide semiconductors(MOSs) are attractive candidates as functional parts and connections in nanodevices.Upon spatial dimensionality reduction, the ubiquitous strain encountered in physical reality may result in ...Metal oxide semiconductors(MOSs) are attractive candidates as functional parts and connections in nanodevices.Upon spatial dimensionality reduction, the ubiquitous strain encountered in physical reality may result in structural instability and thus degrade the performance of MOS. Hence, the basic insight into the structural evolutions of low-dimensional MOS is a prerequisite for extensive applications, which unfortunately remains largely unexplored. Herein, we review the recent progress regarding the mechanical deformation mechanisms in MOSs, such as CuO and ZnO nanowires(NWs). We report the phase transformation of CuO NWs resulting from oxygen vacancy migration under compressive stress and the tensile strain-induced phase transition in ZnO NWs. Moreover, the influence of electron beam irradiation on interpreting the mechanical behaviors is discussed.展开更多
Surface passivation with acidic （NH4）2S solution is shown to be effective in improving the interfacial and electrical properties of HfOE/GaSb metal oxide semiconductor devices. Compared with control samples, the sam...Surface passivation with acidic （NH4）2S solution is shown to be effective in improving the interfacial and electrical properties of HfOE/GaSb metal oxide semiconductor devices. Compared with control samples, the samples treated with acidic （NH4）2S solution show great improvements in gate leakage current, frequency dispersion, border trap density, and interface trap density. These improvements are attributed to the enhancing passivation of the substrates, according to analysis from the perspective of chemical mechanism, X-ray photoelectron spectroscopy, and high-resolution cross-sectional transmission electron microscopy.展开更多
The n-type ultrathin fully depleted silicon-on-insulator(FDSOI) metal-oxide-semiconductor field-effect transistors(MOSFETs),with a Hf_(0.5)Zr_(0.5)O_(2) high dielectric permittivity(high-k) dielectric as gate insulato...The n-type ultrathin fully depleted silicon-on-insulator(FDSOI) metal-oxide-semiconductor field-effect transistors(MOSFETs),with a Hf_(0.5)Zr_(0.5)O_(2) high dielectric permittivity(high-k) dielectric as gate insulator,were fabricated.The total ionizing dose effects were investigated,and an X-ray radiation dose up to 1500 krad(Si) was applied for both long-and short-channel devices.The short-channel devices(0.025-0.100 μm) exhibited less irradiation sensitivity compared with the long-channel devices(0.35-16 μm),leading to a 71% reduction in the irradiation-induced drain current growth and a 26% decrease in the shift of the threshold voltage.It was experimentally demonstrated that the OFF mode is the worst case among the three working conditions(OFF,ON and A110) for short-channel devices.Also,the determined effective electron mobility was enhanced by 38% after X-ray irradiation,attributed to the different compensations for charges triggered by radiation between the highk dielectric and buried oxide.By extracting the carrier mobility,gate length modulation,and source/drain(S/D)parasitic resistance,the degradation mechanism on X-ray irradiation was revealed.Finally,the split capacitance-voltage measurements were used to validate the analysis.展开更多
This work investigated the potential of metal oxide semiconductor(MOS)gas sensors for environmental monitoring of methane.Calibrations were performed under controlled conditions in the lab,and under semi-controlled co...This work investigated the potential of metal oxide semiconductor(MOS)gas sensors for environmental monitoring of methane.Calibrations were performed under controlled conditions in the lab,and under semi-controlled conditions in the field,using a modified head space chamber set-up.Concentrations up to±300 ppm methane were tested.The relationship between sensor conductance and methane concentrations could be very well described using principles from adsorption theory.The adjustable parameters were background conductance G_(0),a sensitivity constant S and a non-ideality coefficient n,where n has a non-rational value between 0 and 1.Sensor behaviour was very different in dry air than in humid air,with the background conductance increasing approximately tenfold and sensitivity decreasing between 20 fold and 80 fold,while the non-ideality coefficient increased from±0.4 to±0.6.Nevertheless,at high methane concentrations comparable conductance values were recorded in dry and humid air.The standard deviation of predicted values was 1.6μS.for the least well described dataset.Using the corresponding calibration curve,a detection limit of 11 ppm is calculated for humid ambient air.This values suggests that MOS sensor are adequately sensitive to be used for methane detection in an agricultural context.展开更多
We describe significant improvements of the photovoltaic properties that were achieved in Al-doped ZnO（AZO）/n-type oxide semiconductor/p-type Cu_2O heterojunction solar cells fabricated using p-type Cu_2O sheets pre...We describe significant improvements of the photovoltaic properties that were achieved in Al-doped ZnO（AZO）/n-type oxide semiconductor/p-type Cu_2O heterojunction solar cells fabricated using p-type Cu_2O sheets prepared by thermally oxidizing Cu sheets. The multicomponent oxide thin film used as the n-type semiconductor layer was prepared with various chemical compositions on non-intentionally heated Cu_2O sheets under various deposition conditions using a pulsed laser deposition method. In Cu_2O-based heterojunction solar cells fabricated using various ternary compounds as the n-type oxide thin-film layer, the best photovoltaic performance was obtained with an n-ZnGa_2O_4 thin-film layer. In most of the Cu_2O-based heterojunction solar cells using multicomponent oxides composed of combinations of various binary compounds, the obtained photovoltaic properties changed gradually as the chemical composition was varied. However, with the ZnO–MgO and Ga_2O_3–Al_2O_3systems, higher conversion efficiencies（á/ as well as a high open circuit voltage（Voc/ were obtained by using a relatively small amount of MgO or Al_2O_3, e.g.,（ZnO）0：91–（MgO）0：09 and（Ga_2O_3/0：975–（Al_2O_3/0：025, respectively. When Cu_2O-based heterojunction solar cells were fabricated using Al_2O_3–Ga_2O_3–MgO–ZnO（AGMZO）multicomponent oxide thin films deposited with metal atomic ratios of 10, 60, 10 and 20 at.% for the Al, Ga, Mg and Zn, respectively, a high Vocof 0.98 V and an á of 4.82% were obtained. In addition, an enhanced á and an improved fill factor could be achieved in AZO/n-type multicomponent oxide/p-type Cu_2O heterojunction solar cells fabricated using Na-doped Cu_2O（Cu_2O：Na） sheets that featured a resistivity controlled by optimizing the post-annealing temperature and duration. Consequently, an á of 6.25% and a Vocof 0.84 V were obtained in a Mg F2/AZO/n-（Ga_2O_3–Al_2O_3//p-Cu_2O：Na heterojunction solar cell fabricated using a Cu_2O：Na sheet with a resistivity of approximately 10 cm and a（Ga_（0：975）A_（l0：025）/2O3 thin film with a thickness of approximately 60 nm.In addition, a Vocof 0.96 V and an á of 5.4% were obtained in a Mg F_2/AZO/n-AGMZO/p-Cu_2O：Na heterojunction solar cell.展开更多
The current article is a review of recent progress and major trends in the field of flexible oxide thin film transistors（TFTs）, fabricating with atomic layer deposition（ALD） processes. The ALD process offers accur...The current article is a review of recent progress and major trends in the field of flexible oxide thin film transistors（TFTs）, fabricating with atomic layer deposition（ALD） processes. The ALD process offers accurate controlling of film thickness and composition as well as ability of achieving excellent uniformity over large areas at relatively low temperatures. First, an introduction is provided on what is the definition of ALD, the difference among other vacuum deposition techniques, and the brief key factors of ALD on flexible devices. Second, considering functional layers in flexible oxide TFT, the ALD process on polymer substrates may improve device performances such as mobility and stability, adopting as buffer layers over the polymer substrate, gate insulators, and active layers. Third, this review consists of the evaluation methods of flexible oxide TFTs under various mechanical stress conditions. The bending radius and repetition cycles are mostly considering for conventional flexible devices. It summarizes how the device has been degraded/changed under various stress types（directions）. The last part of this review suggests a potential of each ALD film, including the releasing stress, the optimization of TFT structure, and the enhancement of device performance. Thus, the functional ALD layers in flexible oxide TFTs offer great possibilities regarding anti-mechanical stress films, along with flexible display and information storage application fields.展开更多
This study investigates the carrier transport of heterojunction channel in oxide semiconductor thin-film transistor(TFT)using the elevated-metal metal-oxide(EMMO)architecture and indium−zinc oxide(InZnO).The heterojun...This study investigates the carrier transport of heterojunction channel in oxide semiconductor thin-film transistor(TFT)using the elevated-metal metal-oxide(EMMO)architecture and indium−zinc oxide(InZnO).The heterojunction band diagram of InZnO bilayer was modified by the cation composition to form the two-dimensional electron gas(2DEG)at the interface quantum well,as verified using a metal−insulator−semiconductor(MIS)device.Although the 2DEG indeed contributes to a higher mobility than the monolayer channel,the competition and cooperation between the gate field and the built-in field strongly affect such mobility-boosting effect,originating from the carrier inelastic collision at the heterojunction interface and the gate field-induced suppression of quantum well.Benefited from the proper energy-band engineering,a high mobility of 84.3 cm2·V^(−1)·s^(−1),a decent threshold voltage(V_(th))of−6.5 V,and a steep subthreshold swing(SS)of 0.29 V/dec were obtained in InZnO-based heterojunction TFT.展开更多
The effect of nitric oxide（NO） annealing on charge traps in the oxide insulator and transition layer in n-type4H–Si C metal–oxide–semiconductor（MOS） devices has been investigated using the time-dependent bias s...The effect of nitric oxide（NO） annealing on charge traps in the oxide insulator and transition layer in n-type4H–Si C metal–oxide–semiconductor（MOS） devices has been investigated using the time-dependent bias stress（TDBS）,capacitance–voltage（C–V）,and secondary ion mass spectroscopy（SIMS）.It is revealed that two main categories of charge traps,near interface oxide traps（Nniot） and oxide traps（Not）,have different responses to the TDBS and C–V characteristics in NO-annealed and Ar-annealed samples.The Nniotare mainly responsible for the hysteresis occurring in the bidirectional C–V characteristics,which are very close to the semiconductor interface and can readily exchange charges with the inner semiconductor.However,Not is mainly responsible for the TDBS induced C–V shifts.Electrons tunneling into the Not are hardly released quickly when suffering TDBS,resulting in the problem of the threshold voltage stability.Compared with the Ar-annealed sample,Nniotcan be significantly suppressed by the NO annealing,but there is little improvement of Not.SIMS results demonstrate that the Nniotare distributed within the transition layer,which correlated with the existence of the excess silicon.During the NO annealing process,the excess Si atoms incorporate into nitrogen in the transition layer,allowing better relaxation of the interface strain and effectively reducing the width of the transition layer and the density of Nniot.展开更多
In this paper the trapping effects in Al2O3/In0.17Al0.83N/GaN MOS-HEMT（here, HEMT stands for high electron mobility transistor） are investigated by frequency-dependent capacitance and conductance analysis. The trap ...In this paper the trapping effects in Al2O3/In0.17Al0.83N/GaN MOS-HEMT（here, HEMT stands for high electron mobility transistor） are investigated by frequency-dependent capacitance and conductance analysis. The trap states are found at both the Al2O3/In AlN and InAlN/GaN interface. Trap states in InAlN/GaN heterostructure are determined to have mixed de-trapping mechanisms, emission, and tunneling. Part of the electrons captured in the trap states are likely to tunnel into the two-dimensional electron gas（2DEG） channel under serious band bending and stronger electric field peak caused by high Al content in the In AlN barrier, which explains the opposite voltage dependence of time constant and relation between the time constant and energy of the trap states.展开更多
Creating gas sensors that are highly selective and function at low temperatures based on semiconductor metal oxides(SMOs)is considered a difficult endeavor,and these sensors are extensively applied in medical diagnosi...Creating gas sensors that are highly selective and function at low temperatures based on semiconductor metal oxides(SMOs)is considered a difficult endeavor,and these sensors are extensively applied in medical diagnosis,industrial manufacturing,and in spacecraft within the aerospace sector.This review article delves into the emerging horizons of chemiresistive gas sensing,particularly focusing on the synergy between polyoxometalates(POMs)and block copolymers in self-assembly for the construction of ordered mesoporous metal oxides(MMOs).It highlights the advancements in gas sensing technology,emphasizing the role of POMs as precursors for MMOs,which offer high sensitivity and selectivity due to their unique physicochemical properties.The review covers various synthetic strategies and their impact on sensor performance,including low-temperature operation,high sensitivity,and selectivity towards specific gases.It also underscores the importance of nanostructure control,heteroatom doping,and the integration of noble metal catalysts in enhancing sensor capabilities.The article concludes with future research directions,suggesting the exploration of a broader range of detectable compounds and the integration of these materials into practical devices for real-world applications.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs),which allow atomic-scale manipulation,have supe-rior electrical and optical properties that challenge the limits of traditional bulk semiconductors like silico...Two-dimensional(2D)transition metal dichalcogenides(TMDs),which allow atomic-scale manipulation,have supe-rior electrical and optical properties that challenge the limits of traditional bulk semiconductors like silicon^([1,2]).As a repre-sentative TMD and a promising 2D channel material for high-performance,scalable p-type transistors,tungsten diselenide(WSe_(2))has attracted considerable academic and industrial interest for its potential in advanced complementary metal−oxide−semiconductor(CMOS)logic technology and in extending Moore’s Law^([3−7]).展开更多
Capacitor-less 2T0C dynamic random-access memory(DRAM)employing oxide semiconductors(OSs)as a channel has great potential in the development of highly scaled three dimensional(3D)-structured devices.However,the use of...Capacitor-less 2T0C dynamic random-access memory(DRAM)employing oxide semiconductors(OSs)as a channel has great potential in the development of highly scaled three dimensional(3D)-structured devices.However,the use of OS and such device structures presents certain challenges,including the trade-off relationship between the field-effect mobility and stability of OSs.Conventional 4-line-based operation of the 2T0C enlarges the entire cell volume and complicates the peripheral circuit.Herein,we proposed an IGO(In-Ga-O)channel 2-line-based 2T0C cell design and operating sequences comparable to those of the conventional Si-channel 1 T1C DRAM.IGO was adopted to achieve high thermal stability above 800℃,and the process conditions were optimized to simultaneously obtain a high μFE of 90.7 cm^(2)·V^(-)1·s^(-1),positive Vth of 0.34 V,superior reliability,and uniformity.The proposed 2-line-based 2T0C DRAM cell successfully exhibited multi-bit operation,with the stored voltage varying from 0 V to 1 V at 0.1 V intervals.Furthermore,for stored voltage intervals of 0.1 V and 0.5 V,the refresh time was 10 s and 1000 s in multi-bit operation;these values were more than 150 and 15000 times longer than those of the conventional Si channel 1T1C DRAM,respectively.A monolithic stacked 2-line-based 2T0C DRAM was fabricated,and a multi-bit operation was confirmed.展开更多
The synthesis,crystal structure and electrical conductivity properties of Fe-doped ZnO powders（in the range of 0.25-15 mol%） were reported in this paper.I-phase samples,which were indexed as single phase with a hexa...The synthesis,crystal structure and electrical conductivity properties of Fe-doped ZnO powders（in the range of 0.25-15 mol%） were reported in this paper.I-phase samples,which were indexed as single phase with a hexagonal（wurtzite） structure in the Fe-doped ZnO binary system,were determined by X-ray diffraction（XRD）.The solubility limit of Fe in the ZnO lattice is 3 mol% at 950℃.The above mixed phase was observed.And the impurity phase was determined as the cubic-ZnFe 2 O 4 phase when compared with standard XRD data using the PDF program.This study focused on single I-phase ZnO samples which were synthesized at 950℃ because the limit of the solubility range is the widest at this temperature.The lattice parameters a and c of the I-phase decreased with Fe-doping concentration.The morphology of the I-phase samples was analyzed with a scanning electron microscope.The grain size of the I-phase samples increased with heat treatment and doping concentration.The electrical conductivity of the pure ZnO and single I-phase samples was investigated using the four-probe dc method at 100-950℃ in air atmosphere.The electrical conductivity values of pure ZnO,0.25 and 3 mol% Fe-doped ZnO samples at 100℃ were 2×10-6,1.7×10-3 and 6.3×10-4 S.cm-1,and at 950℃ they were 3.4,8.5 and 4 S.cm-1,respectively.展开更多
Metal oxide semiconductors(MOSs) are ideal sensing materials for detecting volatile organic compounds due to their low cost, diversity, high stability, and ease of production. However, it remains a grand challenge to ...Metal oxide semiconductors(MOSs) are ideal sensing materials for detecting volatile organic compounds due to their low cost, diversity, high stability, and ease of production. However, it remains a grand challenge to develop the MOSs-based gas sensors for sensing isopropanol with desired performance via a simple, effective,and controllable method. Herein, we reported the preparation of the Al-doped Zn O(AZO)/WO_(3) heterostructure films by directly depositing the AZO coating onto the WO_(3) coating using a strategy of magnetron sputtering. The AZO/WO_(3) heterostructure films were constructed by numbers of irregular nanoparticles that were interconnected with each other. The AZO/WO_(3) heterostructure films-based gas sensors exhibited excellent isopropanolsensing performance with high response, promising selectivity, low detection limit, fast response rate, wide detection range, and ideal reproducibility. The promising isopropanol-sensing performance of the AZO/WO_(3) heterostructure films arises mainly from their high uniformity, unique microstructures with high surface roughness,and the construction of the heterostructure between the AZO and WO_(3) coatings. This work provides a versatile approach to prepare the MOSs-based heterostructure films for assembling the gas sensors.展开更多
Exploring the structure-activity relationship between the performance of gas sensors and the structure of semiconductor metal oxide(SMO)nanomaterials is crucial for understanding and designing gas-sensing materials an...Exploring the structure-activity relationship between the performance of gas sensors and the structure of semiconductor metal oxide(SMO)nanomaterials is crucial for understanding and designing gas-sensing materials and overcoming the application limitations of SMO-based gas sensors.Regulation of a single SMO microstructure provides a promising solution to address this scientific problem due to its controllable composition.In this study,we control the grain boundary(GB)density of Fe_(2)O_(3)nanomaterials using a simple solvothermal method.They have similar chemical compositions and crystal phases,providing an ideal platform for studying the influence of the GB density on the gas-sensing performance.Gas-sensing tests showed that the Fe_(2)O_(3)-1 sensor with medium GB density and the Fe_(2)O_(3)-2 sensor with high GB density had higher sensitivity and selectivity than the Fe_(2)O_(3)-0 sensors with low GB density before reaching the optimal operating temperature.However,when the GB density increased,the response to acetone decreased slightly,whereas the optimal operating temperature decreased.This work highlights the unique performance of the GB density in enhancing the gas sensitivity of a single SMO.展开更多
A 37. 5 MHz differential complementary metal oxide semiconductor （CMOS） crystal oscillator with low power and low phase noise for the radio frequency tuner of digital radio broadcasting digital radio mondiale （DRAM...A 37. 5 MHz differential complementary metal oxide semiconductor （CMOS） crystal oscillator with low power and low phase noise for the radio frequency tuner of digital radio broadcasting digital radio mondiale （DRAM） and digital audio broadcasting （DAB） systems is realized and characterized. The conventional cross-coupled n-type metal oxide semiconductor （NMOS） transistors are replaced by p-type metal oxide semiconductor （PMOS） transistors to decrease the phase noise in the core part of the crystal oscillator. A symmetry structure of the current mirror is adopted to increase the stability of direct current. The amplitude detecting circuit made up of a single- stage CMOS operational transconductance amplifier （OTA） and a simple amplitude detector is used to improve the current accuracy of the output signals. The chip is fabricated in a 0. 18- pxn CMOS process, and the total chip size is 0. 35 mm x 0. 3 mm. Under a supply voltage of 1.8 V, the measured power consumption is 3.6 mW including the output buffer for 50 testing loads. The proposed crystal oscillator exhibits a low phase noise of - 134. 7 dBc/Hz at 1-kHz offset from the center frequency of 37. 5 MHz.展开更多
A low noise, high conversion gain down-conversion mixer for WLAN 802.11a applications, which adopts the high intermediate frequency （IF） topology, is presented. The input radio frequency （RF）band, local oscillator...A low noise, high conversion gain down-conversion mixer for WLAN 802.11a applications, which adopts the high intermediate frequency （IF） topology, is presented. The input radio frequency （RF）band, local oscillator（LO）frequency band and output IF are 5.15 to 5.35, 4.15 to 4.35 and 1 GHz, respectively. Source resistive degeneration technique and pseudo-differential Gilbert topology are used to achieve high linearity, and, current bleeding technique and LC resonant loads are used to acquire a low noise figure. In addition, the mixer adopts a common-source transistor pair cross-stacked with a source follow pair（CSSF）circuit as an output buffer to enhance the mixer＇s conversion gain but not deteriorate the other performances. The mixer is implemented in 0.18 μm RF CMOS（complementary metal oxide semiconductor transistor）technology and the chip area of the mixer including all bonding pads is 580 μm×1 185 μm. The measured results show that under a 1.8 V supply, the conversion gain is 10.1 dB; the input 1 dB compression point and the input-referred third-order intercept point are-3.5 and 5.3 dBm, respectively; the single side band （SSB）noise figure （NF）is 8.65 dB, and the core current consumption is 3.8 mA.展开更多
基金This work is supported by This work was supported by the National Key R&D Program of China(Nos.2020YFB2008604 and 2021YFB3202500)the National Natural Science Foundation of China(Nos.61874034 and 51861135105)+1 种基金the International Science and Technology Cooperation Program of Shanghai Science and Technology Innovation Action Plan(No.21520713300)Fudan University-CIOMP Joint Fund(E02632Y7H0).
文摘With the rapid development of the Internet of Things,there is a great demand for portable gas sensors.Metal oxide semiconductors(MOS)are one of the most traditional and well-studied gas sensing materials and have been widely used to prepare various commercial gas sensors.However,it is limited by high operating temperature.The current research works are directed towards fabricating high-performance flexible room-temperature(FRT)gas sensors,which are effective in simplifying the structure of MOS-based sensors,reducing power consumption,and expanding the application of portable devices.This article presents the recent research progress of MOS-based FRT gas sensors in terms of sensing mechanism,performance,flexibility characteristics,and applications.This review comprehensively summarizes and discusses five types of MOS-based FRT gas sensors,including pristine MOS,noble metal nanoparticles modified MOS,organic polymers modified MOS,carbon-based materials(carbon nanotubes and graphene derivatives)modified MOS,and two-dimensional transition metal dichalcogenides materials modified MOS.The effect of light-illuminated to improve gas sensing performance is further discussed.Furthermore,the applications and future perspectives of FRT gas sensors are also discussed.
基金support from the Australian Research Council through its DECRA(DE210100930)Discovery Project (DP200101900)+2 种基金Lau-reate Fellowship (FL190100139) schemesfinancial support from Research Donation Generic(2020003431) from the Faculty of EngineeringArchitecture and Information Technology,The University of Queensland
文摘As a kind of valuable chemicals,hydrogen peroxide(H2O2)has aroused growing attention in many fields.However,H2O2 production via traditional anthraquinone process suffers from challenges of large energy consumption and heavy carbon footprint.Alternatively,photoelectrocatalytic(PEC)production of H2O2 has shown great promises to make H2O2 a renewable fuel to store solar energy.Transition‐metal‐oxide(TMO)semiconductor based photoelectrocatalysts are among the most promising candidates for PEC H2O2 production.In this work,the fundamentals of H2O2 synthesis through PEC process are briefly introduced,followed by the state‐of‐the‐art of TMO semiconductor based photoelectrocatalysts for PEC production H2O2.Then,the progress on H2O2 fuel cells from on‐site PEC production is presented.Furthermore,the challenges and future perspectives of PEC H2O2 production are discussed.This review aims to provide inspiration for the PEC production of H2O2 as a renewable solar fuel.
基金supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF-2020M3H4A3081867)the industry technology R&D program (20006400) funded by the Ministry of Trade,Industry and Energy (MOTIE, Korea)+2 种基金the project number 20010402 funded by the Ministry of Trade,Industry and Energy (MOTIE, Korea)the Industry Technology R&D program (#20010371) funded by the Ministry of Trade,Industry and Energy (MOTIE, Republic of Korea)the Technology Innovation Program (20017382) funded By the Ministryof Trade,Industry and Energy (MOTIE, Korea)
文摘Since the first report of amorphous In–Ga–Zn–O based thin film transistors,interest in oxide semiconductors has grown.They offer high mobility,low off-current,low process temperature,and wide flexibility for compositions and processes.Unfortunately,depositing oxide semiconductors using conventional processes like physical vapor deposition leads to problematic issues,especially for high-resolution displays and highly integrated memory devices.Conventional approaches have limited process flexibility and poor conformality on structured surfaces.Atomic layer deposition(ALD)is an advanced technique which can provide conformal,thickness-controlled,and high-quality thin film deposition.Accordingly,studies on ALD based oxide semiconductors have dramatically increased recently.Even so,the relationships between the film properties of ALD-oxide semiconductors and the main variables associated with deposition are still poorly understood,as are many issues related to applications.In this review,to introduce ALD-oxide semiconductors,we provide:(a)a brief summary of the history and importance of ALD-based oxide semiconductors in industry,(b)a discussion of the benefits of ALD for oxide semiconductor deposition(in-situ composition control in vertical distribution/vertical structure engineering/chemical reaction and film properties/insulator and interface engineering),and(c)an explanation of the challenging issues of scaling oxide semiconductors and ALD for industrial applications.This review provides valuable perspectives for researchers who have interest in semiconductor materials and electronic device applications,and the reasons ALD is important to applications of oxide semiconductors.
基金supported by the National Natural Science Foundation of China (52071237, 12074290, 51871169, 51671148, 11674251, 51601132, 52101021, and 12104345)the Natural Science Foundation of Jiangsu Province (BK20191187)+2 种基金the Fundamental Research Funds for the Central Universities (2042019kf0190)the Science and Technology Program of Shenzhen (JCYJ20190808150407522)the China Postdoctoral Science Foundation (2019M652685)。
文摘Metal oxide semiconductors(MOSs) are attractive candidates as functional parts and connections in nanodevices.Upon spatial dimensionality reduction, the ubiquitous strain encountered in physical reality may result in structural instability and thus degrade the performance of MOS. Hence, the basic insight into the structural evolutions of low-dimensional MOS is a prerequisite for extensive applications, which unfortunately remains largely unexplored. Herein, we review the recent progress regarding the mechanical deformation mechanisms in MOSs, such as CuO and ZnO nanowires(NWs). We report the phase transformation of CuO NWs resulting from oxygen vacancy migration under compressive stress and the tensile strain-induced phase transition in ZnO NWs. Moreover, the influence of electron beam irradiation on interpreting the mechanical behaviors is discussed.
基金supported by the State Key Development Program for Basic Research of China(Grant No.2011CBA00602)the Major Project of the NationalScience and Technology of China(Grant No.2011ZX02708-002)
文摘Surface passivation with acidic （NH4）2S solution is shown to be effective in improving the interfacial and electrical properties of HfOE/GaSb metal oxide semiconductor devices. Compared with control samples, the samples treated with acidic （NH4）2S solution show great improvements in gate leakage current, frequency dispersion, border trap density, and interface trap density. These improvements are attributed to the enhancing passivation of the substrates, according to analysis from the perspective of chemical mechanism, X-ray photoelectron spectroscopy, and high-resolution cross-sectional transmission electron microscopy.
基金financially supported by the National Natural Science Foundation of China (Nos.61874135,61904194 and 11905287)the National Major Project of Science and Technology of China (No.2017ZX02315001)+1 种基金the Youth Innovation Promotion Association,CAS (No.Y9YQ01R004)the Opening Project of Key Laboratory of Microelectronic Devices & Integrated Technology,Institute of Microelectronics,CAS (No.Y9YS05X002)。
文摘The n-type ultrathin fully depleted silicon-on-insulator(FDSOI) metal-oxide-semiconductor field-effect transistors(MOSFETs),with a Hf_(0.5)Zr_(0.5)O_(2) high dielectric permittivity(high-k) dielectric as gate insulator,were fabricated.The total ionizing dose effects were investigated,and an X-ray radiation dose up to 1500 krad(Si) was applied for both long-and short-channel devices.The short-channel devices(0.025-0.100 μm) exhibited less irradiation sensitivity compared with the long-channel devices(0.35-16 μm),leading to a 71% reduction in the irradiation-induced drain current growth and a 26% decrease in the shift of the threshold voltage.It was experimentally demonstrated that the OFF mode is the worst case among the three working conditions(OFF,ON and A110) for short-channel devices.Also,the determined effective electron mobility was enhanced by 38% after X-ray irradiation,attributed to the different compensations for charges triggered by radiation between the highk dielectric and buried oxide.By extracting the carrier mobility,gate length modulation,and source/drain(S/D)parasitic resistance,the degradation mechanism on X-ray irradiation was revealed.Finally,the split capacitance-voltage measurements were used to validate the analysis.
基金supported by the European Union’s Horizon 2020 research and innovation programme[grant agreement No.825325].
文摘This work investigated the potential of metal oxide semiconductor(MOS)gas sensors for environmental monitoring of methane.Calibrations were performed under controlled conditions in the lab,and under semi-controlled conditions in the field,using a modified head space chamber set-up.Concentrations up to±300 ppm methane were tested.The relationship between sensor conductance and methane concentrations could be very well described using principles from adsorption theory.The adjustable parameters were background conductance G_(0),a sensitivity constant S and a non-ideality coefficient n,where n has a non-rational value between 0 and 1.Sensor behaviour was very different in dry air than in humid air,with the background conductance increasing approximately tenfold and sensitivity decreasing between 20 fold and 80 fold,while the non-ideality coefficient increased from±0.4 to±0.6.Nevertheless,at high methane concentrations comparable conductance values were recorded in dry and humid air.The standard deviation of predicted values was 1.6μS.for the least well described dataset.Using the corresponding calibration curve,a detection limit of 11 ppm is calculated for humid ambient air.This values suggests that MOS sensor are adequately sensitive to be used for methane detection in an agricultural context.
文摘We describe significant improvements of the photovoltaic properties that were achieved in Al-doped ZnO（AZO）/n-type oxide semiconductor/p-type Cu_2O heterojunction solar cells fabricated using p-type Cu_2O sheets prepared by thermally oxidizing Cu sheets. The multicomponent oxide thin film used as the n-type semiconductor layer was prepared with various chemical compositions on non-intentionally heated Cu_2O sheets under various deposition conditions using a pulsed laser deposition method. In Cu_2O-based heterojunction solar cells fabricated using various ternary compounds as the n-type oxide thin-film layer, the best photovoltaic performance was obtained with an n-ZnGa_2O_4 thin-film layer. In most of the Cu_2O-based heterojunction solar cells using multicomponent oxides composed of combinations of various binary compounds, the obtained photovoltaic properties changed gradually as the chemical composition was varied. However, with the ZnO–MgO and Ga_2O_3–Al_2O_3systems, higher conversion efficiencies（á/ as well as a high open circuit voltage（Voc/ were obtained by using a relatively small amount of MgO or Al_2O_3, e.g.,（ZnO）0：91–（MgO）0：09 and（Ga_2O_3/0：975–（Al_2O_3/0：025, respectively. When Cu_2O-based heterojunction solar cells were fabricated using Al_2O_3–Ga_2O_3–MgO–ZnO（AGMZO）multicomponent oxide thin films deposited with metal atomic ratios of 10, 60, 10 and 20 at.% for the Al, Ga, Mg and Zn, respectively, a high Vocof 0.98 V and an á of 4.82% were obtained. In addition, an enhanced á and an improved fill factor could be achieved in AZO/n-type multicomponent oxide/p-type Cu_2O heterojunction solar cells fabricated using Na-doped Cu_2O（Cu_2O：Na） sheets that featured a resistivity controlled by optimizing the post-annealing temperature and duration. Consequently, an á of 6.25% and a Vocof 0.84 V were obtained in a Mg F2/AZO/n-（Ga_2O_3–Al_2O_3//p-Cu_2O：Na heterojunction solar cell fabricated using a Cu_2O：Na sheet with a resistivity of approximately 10 cm and a（Ga_（0：975）A_（l0：025）/2O3 thin film with a thickness of approximately 60 nm.In addition, a Vocof 0.96 V and an á of 5.4% were obtained in a Mg F_2/AZO/n-AGMZO/p-Cu_2O：Na heterojunction solar cell.
基金supported by the National Research Foundation of Korea(NRF)(No.NRF-2017RID1A1B03034035)the Ministry of Trade,Industry&Energy(No.#10051403)the Korea Semiconductor Research Consortium
文摘The current article is a review of recent progress and major trends in the field of flexible oxide thin film transistors（TFTs）, fabricating with atomic layer deposition（ALD） processes. The ALD process offers accurate controlling of film thickness and composition as well as ability of achieving excellent uniformity over large areas at relatively low temperatures. First, an introduction is provided on what is the definition of ALD, the difference among other vacuum deposition techniques, and the brief key factors of ALD on flexible devices. Second, considering functional layers in flexible oxide TFT, the ALD process on polymer substrates may improve device performances such as mobility and stability, adopting as buffer layers over the polymer substrate, gate insulators, and active layers. Third, this review consists of the evaluation methods of flexible oxide TFTs under various mechanical stress conditions. The bending radius and repetition cycles are mostly considering for conventional flexible devices. It summarizes how the device has been degraded/changed under various stress types（directions）. The last part of this review suggests a potential of each ALD film, including the releasing stress, the optimization of TFT structure, and the enhancement of device performance. Thus, the functional ALD layers in flexible oxide TFTs offer great possibilities regarding anti-mechanical stress films, along with flexible display and information storage application fields.
基金supported by National Key Research and Development Program(2021YFB3600802)Shenzhen Municipal Scientific Program(JSGG20220831103803007,SGDX20211123145404006)Guangdong Basic and Applied Basic Research Foundation(2022A1515110029)
文摘This study investigates the carrier transport of heterojunction channel in oxide semiconductor thin-film transistor(TFT)using the elevated-metal metal-oxide(EMMO)architecture and indium−zinc oxide(InZnO).The heterojunction band diagram of InZnO bilayer was modified by the cation composition to form the two-dimensional electron gas(2DEG)at the interface quantum well,as verified using a metal−insulator−semiconductor(MIS)device.Although the 2DEG indeed contributes to a higher mobility than the monolayer channel,the competition and cooperation between the gate field and the built-in field strongly affect such mobility-boosting effect,originating from the carrier inelastic collision at the heterojunction interface and the gate field-induced suppression of quantum well.Benefited from the proper energy-band engineering,a high mobility of 84.3 cm2·V^(−1)·s^(−1),a decent threshold voltage(V_(th))of−6.5 V,and a steep subthreshold swing(SS)of 0.29 V/dec were obtained in InZnO-based heterojunction TFT.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61404098 and 61274079)the Doctoral Fund of Ministry of Education of China(Grant No.20130203120017)+2 种基金the National Key Basic Research Program of China(Grant No.2015CB759600)the National Grid Science&Technology Project,China(Grant No.SGRI-WD-71-14-018)the Key Specific Project in the National Science&Technology Program,China(Grant Nos.2013ZX02305002-002 and 2015CB759600)
文摘The effect of nitric oxide（NO） annealing on charge traps in the oxide insulator and transition layer in n-type4H–Si C metal–oxide–semiconductor（MOS） devices has been investigated using the time-dependent bias stress（TDBS）,capacitance–voltage（C–V）,and secondary ion mass spectroscopy（SIMS）.It is revealed that two main categories of charge traps,near interface oxide traps（Nniot） and oxide traps（Not）,have different responses to the TDBS and C–V characteristics in NO-annealed and Ar-annealed samples.The Nniotare mainly responsible for the hysteresis occurring in the bidirectional C–V characteristics,which are very close to the semiconductor interface and can readily exchange charges with the inner semiconductor.However,Not is mainly responsible for the TDBS induced C–V shifts.Electrons tunneling into the Not are hardly released quickly when suffering TDBS,resulting in the problem of the threshold voltage stability.Compared with the Ar-annealed sample,Nniotcan be significantly suppressed by the NO annealing,but there is little improvement of Not.SIMS results demonstrate that the Nniotare distributed within the transition layer,which correlated with the existence of the excess silicon.During the NO annealing process,the excess Si atoms incorporate into nitrogen in the transition layer,allowing better relaxation of the interface strain and effectively reducing the width of the transition layer and the density of Nniot.
基金Project supported by the Program for National Natural Science Foundation of China(Grant Nos.61404100 and 61306017)
文摘In this paper the trapping effects in Al2O3/In0.17Al0.83N/GaN MOS-HEMT（here, HEMT stands for high electron mobility transistor） are investigated by frequency-dependent capacitance and conductance analysis. The trap states are found at both the Al2O3/In AlN and InAlN/GaN interface. Trap states in InAlN/GaN heterostructure are determined to have mixed de-trapping mechanisms, emission, and tunneling. Part of the electrons captured in the trap states are likely to tunnel into the two-dimensional electron gas（2DEG） channel under serious band bending and stronger electric field peak caused by high Al content in the In AlN barrier, which explains the opposite voltage dependence of time constant and relation between the time constant and energy of the trap states.
基金financial support from the Program for the Development of Science and Technology of Jilin Province(YDZJ202401335ZYTS)the Fundamental Research Funds for the Central Universities
文摘Creating gas sensors that are highly selective and function at low temperatures based on semiconductor metal oxides(SMOs)is considered a difficult endeavor,and these sensors are extensively applied in medical diagnosis,industrial manufacturing,and in spacecraft within the aerospace sector.This review article delves into the emerging horizons of chemiresistive gas sensing,particularly focusing on the synergy between polyoxometalates(POMs)and block copolymers in self-assembly for the construction of ordered mesoporous metal oxides(MMOs).It highlights the advancements in gas sensing technology,emphasizing the role of POMs as precursors for MMOs,which offer high sensitivity and selectivity due to their unique physicochemical properties.The review covers various synthetic strategies and their impact on sensor performance,including low-temperature operation,high sensitivity,and selectivity towards specific gases.It also underscores the importance of nanostructure control,heteroatom doping,and the integration of noble metal catalysts in enhancing sensor capabilities.The article concludes with future research directions,suggesting the exploration of a broader range of detectable compounds and the integration of these materials into practical devices for real-world applications.
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs),which allow atomic-scale manipulation,have supe-rior electrical and optical properties that challenge the limits of traditional bulk semiconductors like silicon^([1,2]).As a repre-sentative TMD and a promising 2D channel material for high-performance,scalable p-type transistors,tungsten diselenide(WSe_(2))has attracted considerable academic and industrial interest for its potential in advanced complementary metal−oxide−semiconductor(CMOS)logic technology and in extending Moore’s Law^([3−7]).
基金supported by the Technology Innovation Program(Grant Nos.20017382 and 20023023)funded by the Ministry of Trade,Industry&Energy(MOTIE,Republic of Korea)supported by a National Research Foundation of Korea(NRF)grant funded by the Korean Government(MSIT)(Grant No.RS-2023-00260527).
文摘Capacitor-less 2T0C dynamic random-access memory(DRAM)employing oxide semiconductors(OSs)as a channel has great potential in the development of highly scaled three dimensional(3D)-structured devices.However,the use of OS and such device structures presents certain challenges,including the trade-off relationship between the field-effect mobility and stability of OSs.Conventional 4-line-based operation of the 2T0C enlarges the entire cell volume and complicates the peripheral circuit.Herein,we proposed an IGO(In-Ga-O)channel 2-line-based 2T0C cell design and operating sequences comparable to those of the conventional Si-channel 1 T1C DRAM.IGO was adopted to achieve high thermal stability above 800℃,and the process conditions were optimized to simultaneously obtain a high μFE of 90.7 cm^(2)·V^(-)1·s^(-1),positive Vth of 0.34 V,superior reliability,and uniformity.The proposed 2-line-based 2T0C DRAM cell successfully exhibited multi-bit operation,with the stored voltage varying from 0 V to 1 V at 0.1 V intervals.Furthermore,for stored voltage intervals of 0.1 V and 0.5 V,the refresh time was 10 s and 1000 s in multi-bit operation;these values were more than 150 and 15000 times longer than those of the conventional Si channel 1T1C DRAM,respectively.A monolithic stacked 2-line-based 2T0C DRAM was fabricated,and a multi-bit operation was confirmed.
基金supported by the Research Foundation of Erciyes University (Kayseri,Turkey)
文摘The synthesis,crystal structure and electrical conductivity properties of Fe-doped ZnO powders（in the range of 0.25-15 mol%） were reported in this paper.I-phase samples,which were indexed as single phase with a hexagonal（wurtzite） structure in the Fe-doped ZnO binary system,were determined by X-ray diffraction（XRD）.The solubility limit of Fe in the ZnO lattice is 3 mol% at 950℃.The above mixed phase was observed.And the impurity phase was determined as the cubic-ZnFe 2 O 4 phase when compared with standard XRD data using the PDF program.This study focused on single I-phase ZnO samples which were synthesized at 950℃ because the limit of the solubility range is the widest at this temperature.The lattice parameters a and c of the I-phase decreased with Fe-doping concentration.The morphology of the I-phase samples was analyzed with a scanning electron microscope.The grain size of the I-phase samples increased with heat treatment and doping concentration.The electrical conductivity of the pure ZnO and single I-phase samples was investigated using the four-probe dc method at 100-950℃ in air atmosphere.The electrical conductivity values of pure ZnO,0.25 and 3 mol% Fe-doped ZnO samples at 100℃ were 2×10-6,1.7×10-3 and 6.3×10-4 S.cm-1,and at 950℃ they were 3.4,8.5 and 4 S.cm-1,respectively.
基金financially supported by the National Natural Science Foundation of China (Nos.52172094 and 22209105)Shanghai Municipal Natural Science Foundation (No.21ZR1426700)the “Shuguang” Program of Shanghai Education Commission (No.19SG46)。
文摘Metal oxide semiconductors(MOSs) are ideal sensing materials for detecting volatile organic compounds due to their low cost, diversity, high stability, and ease of production. However, it remains a grand challenge to develop the MOSs-based gas sensors for sensing isopropanol with desired performance via a simple, effective,and controllable method. Herein, we reported the preparation of the Al-doped Zn O(AZO)/WO_(3) heterostructure films by directly depositing the AZO coating onto the WO_(3) coating using a strategy of magnetron sputtering. The AZO/WO_(3) heterostructure films were constructed by numbers of irregular nanoparticles that were interconnected with each other. The AZO/WO_(3) heterostructure films-based gas sensors exhibited excellent isopropanolsensing performance with high response, promising selectivity, low detection limit, fast response rate, wide detection range, and ideal reproducibility. The promising isopropanol-sensing performance of the AZO/WO_(3) heterostructure films arises mainly from their high uniformity, unique microstructures with high surface roughness,and the construction of the heterostructure between the AZO and WO_(3) coatings. This work provides a versatile approach to prepare the MOSs-based heterostructure films for assembling the gas sensors.
基金financially supported by the National Natural Science Foundation of China(Nos.21571119 and 22209102)the Program for New Century Excellent Talents in University of Ministry of Education of China(No.NCET-12-1035)+2 种基金the Natural Science Foundation of Shanxi Province(Nos.202203021211253 and 20210302124473)the Postgraduate Innovation Project of Shanxi Normal University(No.2022XSY022)China Postdoctoral Science Foundation(No.2021M691366)。
文摘Exploring the structure-activity relationship between the performance of gas sensors and the structure of semiconductor metal oxide(SMO)nanomaterials is crucial for understanding and designing gas-sensing materials and overcoming the application limitations of SMO-based gas sensors.Regulation of a single SMO microstructure provides a promising solution to address this scientific problem due to its controllable composition.In this study,we control the grain boundary(GB)density of Fe_(2)O_(3)nanomaterials using a simple solvothermal method.They have similar chemical compositions and crystal phases,providing an ideal platform for studying the influence of the GB density on the gas-sensing performance.Gas-sensing tests showed that the Fe_(2)O_(3)-1 sensor with medium GB density and the Fe_(2)O_(3)-2 sensor with high GB density had higher sensitivity and selectivity than the Fe_(2)O_(3)-0 sensors with low GB density before reaching the optimal operating temperature.However,when the GB density increased,the response to acetone decreased slightly,whereas the optimal operating temperature decreased.This work highlights the unique performance of the GB density in enhancing the gas sensitivity of a single SMO.
基金The National Natural Science Foundation of China(No. 61106024)the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20090092120012)the Science and Technology Program of South east University (No. KJ2010402)
文摘A 37. 5 MHz differential complementary metal oxide semiconductor （CMOS） crystal oscillator with low power and low phase noise for the radio frequency tuner of digital radio broadcasting digital radio mondiale （DRAM） and digital audio broadcasting （DAB） systems is realized and characterized. The conventional cross-coupled n-type metal oxide semiconductor （NMOS） transistors are replaced by p-type metal oxide semiconductor （PMOS） transistors to decrease the phase noise in the core part of the crystal oscillator. A symmetry structure of the current mirror is adopted to increase the stability of direct current. The amplitude detecting circuit made up of a single- stage CMOS operational transconductance amplifier （OTA） and a simple amplitude detector is used to improve the current accuracy of the output signals. The chip is fabricated in a 0. 18- pxn CMOS process, and the total chip size is 0. 35 mm x 0. 3 mm. Under a supply voltage of 1.8 V, the measured power consumption is 3.6 mW including the output buffer for 50 testing loads. The proposed crystal oscillator exhibits a low phase noise of - 134. 7 dBc/Hz at 1-kHz offset from the center frequency of 37. 5 MHz.
基金The Science and Technology Program of Zhejiang Province (No.2008C16017)
文摘A low noise, high conversion gain down-conversion mixer for WLAN 802.11a applications, which adopts the high intermediate frequency （IF） topology, is presented. The input radio frequency （RF）band, local oscillator（LO）frequency band and output IF are 5.15 to 5.35, 4.15 to 4.35 and 1 GHz, respectively. Source resistive degeneration technique and pseudo-differential Gilbert topology are used to achieve high linearity, and, current bleeding technique and LC resonant loads are used to acquire a low noise figure. In addition, the mixer adopts a common-source transistor pair cross-stacked with a source follow pair（CSSF）circuit as an output buffer to enhance the mixer＇s conversion gain but not deteriorate the other performances. The mixer is implemented in 0.18 μm RF CMOS（complementary metal oxide semiconductor transistor）technology and the chip area of the mixer including all bonding pads is 580 μm×1 185 μm. The measured results show that under a 1.8 V supply, the conversion gain is 10.1 dB; the input 1 dB compression point and the input-referred third-order intercept point are-3.5 and 5.3 dBm, respectively; the single side band （SSB）noise figure （NF）is 8.65 dB, and the core current consumption is 3.8 mA.
