A silicon-based germanium(Ge)photodetector working for C and L bands is proposed in this paper.The device fea-tures a novel asymmetric PIN structure,which contributes to a more optimized electric field distribution in...A silicon-based germanium(Ge)photodetector working for C and L bands is proposed in this paper.The device fea-tures a novel asymmetric PIN structure,which contributes to a more optimized electric field distribution in Ge and a shorter effective width of depleted region.Meanwhile,the optical structure is designed carefully to enhance responsivity for broad-band.Under-7 V,where the weak avalanche process happens,the responsivity of our device is 1.49 and 1.16 A/W at 1550 and 1600 nm,with bandwidth of 47.1 and 44.5 GHz,respectively.These performances demonstrate the significant application poten-tial of the device in optical communication systems.展开更多
An investigation of germanium-tin(GeSn) on silicon p–i–n photodetectors with a high-quality Ge0.94 Sn0.06 absorbing layer is reported. The Ge Sn photodetector reached a responsivity as high as 0.45 A/W at the wavele...An investigation of germanium-tin(GeSn) on silicon p–i–n photodetectors with a high-quality Ge0.94 Sn0.06 absorbing layer is reported. The Ge Sn photodetector reached a responsivity as high as 0.45 A/W at the wavelength of 1550 nm and 0.12 A/W at the wavelength of 2 μm. A cycle annealing technology was applied to improve the quality of the epitaxial layer during the growth process by molecular beam epitaxy. A low dark-current density under 1 V reverse bias about 0.078 A/cm2 was achieved at room temperature. Furthermore, the Ge Sn photodetector could detect a wide spectrum region and the cutoff wavelength reached to about 2.3 μm. This work has great importance in silicon-based short-wave infrared detection.展开更多
High-performance germanium(Ge)waveguide photodetectors are designed and fabricated utilizing the inductivegain-peaking technique.With the appropriate integrated inductors,the 3-dB bandwidth of photodetectors is signif...High-performance germanium(Ge)waveguide photodetectors are designed and fabricated utilizing the inductivegain-peaking technique.With the appropriate integrated inductors,the 3-dB bandwidth of photodetectors is significantly improved owing to the inductive-gain-peaking effect without any compromises to the dark current and optical responsivity.Measured 3-dB bandwidth up to 75 GHz is realized and clear open eye diagrams at 64 Gbps are observed.In this work,the relationship between the frequency response and large signal transmission characteristics on the integrated inductors of Ge waveguide photodetectors is investigated,which indicates the high-speed performance of photodetectors using the inductive-gainpeaking technique.展开更多
Beta-gallium oxide(β-Ga_(2)O_(3))thin films were deposited on c-plane(0001)sapphire substrates with different mis-cut angles along<>by metal-organic chemical vapor deposition(MOCVD).The structural properties an...Beta-gallium oxide(β-Ga_(2)O_(3))thin films were deposited on c-plane(0001)sapphire substrates with different mis-cut angles along<>by metal-organic chemical vapor deposition(MOCVD).The structural properties and surface morphology of as-grownβ-Ga_(2)O_(3)thin films were investigated in detail.It was found that by using thin buffer layer and mis-cut substrate technology,the full width at half maximum(FWHM)of the()diffraction peak of theβ-Ga_(2)O_(3)film is decreased from 2°on c-plane(0001)Al_(2)O_(3)substrate to 0.64°on an 8°off-angled c-plane(0001)Al_(2)O_(3)substrate.The surface root-mean-square(RMS)roughness can also be improved greatly and the value is 1.27 nm for 8°off-angled c-plane(0001)Al_(2)O_(3)substrate.Room temper-ature photoluminescence(PL)was observed,which was attributed to the self-trapped excitons formed by oxygen and gallium vacancies in the film.The ultraviolet-blue PL intensity related with oxygen and gallium vacancies is decreased with the increas-ing mis-cut angle,which is in agreement with the improved crystal quality measured by high resolution X-ray diffraction(HR-XRD).The present results provide a route for growing high qualityβ-Ga_(2)O_(3)film on Al_(2)O_(3)substrate.展开更多
A novel structure of silicon-riched nitride(SRN)/silicon-riched oxide(SRO) is proposed and prepared using RF reactive magnetron co-sputtering. High temperature annealing of SRN/SRO multilayers leads to formation of Si...A novel structure of silicon-riched nitride(SRN)/silicon-riched oxide(SRO) is proposed and prepared using RF reactive magnetron co-sputtering. High temperature annealing of SRN/SRO multilayers leads to formation of Si nanocrystals(NC) from isolating SRN and SRO layers simultaneously, which efficiently improves carrier transport ability compared to conventional SRN/Si_3N_4 counterpart. Micro-Raman scattering analysis reveals that SRN layer has dominating number of denser and smaller Si NCs, while SRO layer has relatively less, sparser and bigger Si NCs, as confirmed by high resolution transmission electron microscopy observation. The substitute SRO layers for Si_3N_4 counterparts significantly increase the amount of Si NCs as well as crystallization ratio in SRN layers; while the average Si NC size can be well controlled by the thickness of SRN layers and the content of N, and hence an obvious stronger absorption in UV region for the novel structure can be observed in absorption spectra. The I-V characteristics show that the current of hybrid SRN/SRO system increases up to 2 orders of magnitude at 1 V and even 5 orders of magnitude at 4 V compared to that of SRN/Si_3N_4 structure. Si NCs in Si Oylayers provide a transport pathway for adjacent Si NCs in Si Nxlayers. The obvious advantage in carrier transportation suggests that SRN/SRO hybrid system could be a promising structure and platform to build Si nanostructured solar cells.展开更多
Si photonics is a promising technological approach to realize a photonic integrated circuits on Si substrate with small footprint,high performance,low cost,and being highly compatible with Si complementary metal oxide...Si photonics is a promising technological approach to realize a photonic integrated circuits on Si substrate with small footprint,high performance,low cost,and being highly compatible with Si complementary metal oxide semiconductor(CMOS)technology[1].Because of good compatibility of Si and the relatively high absorption coefficient in the near-infrared region,Ge waveguide photodiode on Si is almost the only option for optical receiving in Si photonic integrated circuits.For a high performance Ge photodiode,the critical parameters are optical responsivity,3-dB bandwidth,and dark current.展开更多
Transistor's invention revolutionized global society by spawning electronics industry. John Bardeen is among one of the inventors of transistor. He was a genius and one of the most influential semiconductor Physic...Transistor's invention revolutionized global society by spawning electronics industry. John Bardeen is among one of the inventors of transistor. He was a genius and one of the most influential semiconductor Physicist of 20 th century who won two Nobel prizes in Physics.展开更多
In this work,a two-step metal organic chemical vapor deposition(MOCVD)method was applied for growingβ-Ga_(2)O_(3) film on c-plane sapphire.Optimized buffer layer growth temperature(T_(B))was found at 700℃ and theβ-...In this work,a two-step metal organic chemical vapor deposition(MOCVD)method was applied for growingβ-Ga_(2)O_(3) film on c-plane sapphire.Optimized buffer layer growth temperature(T_(B))was found at 700℃ and theβ-Ga_(2)O_(3) film with full width at half maximum(FWHM)of 0.66°was achieved.A metal−semiconductor−metal(MSM)solar-blind photodetector(PD)was fabricated based on theβ-Ga_(2)O_(3) film.Ultrahigh responsivity of 1422 A/W@254 nm and photo-to-dark current ratio(PDCR)of 10^(6) at 10 V bias were obtained.The detectivity of 2.5×10^(15) Jones proved that the photodetector has outstanding performance in detecting weak signals.Moreover,the photodetector exhibited superior wavelength selectivity with rejection ratio(R_(250 nm)/R_(400 nm))of 105.These results indicate that the two-step method is a promising approach for preparation of high-qualityβ-Ga_(2)O_(3)films for high-performance solar-blind photodetectors.展开更多
A GeSn nanostrip grown by the rapid melting growth method has gradient Sn content along the strip,a very attractive approach for making an infrared broad-spectrum light source.In this work,by applying the Sn content d...A GeSn nanostrip grown by the rapid melting growth method has gradient Sn content along the strip,a very attractive approach for making an infrared broad-spectrum light source.In this work,by applying the Sn content distribution strategy.展开更多
Perovskite single crystals(PSCs)have attracted significant interest for next-generation radiation detection.However,the lack of in-depth crystal growth kinetics of PSCs limits the development of high-quality PSCs.Here...Perovskite single crystals(PSCs)have attracted significant interest for next-generation radiation detection.However,the lack of in-depth crystal growth kinetics of PSCs limits the development of high-quality PSCs.Here,with an in-situ real-time monitoring system for MAPbBr3 PSCs growth during the antisolvent vapor-assisted crystallization(AVC)process,the growth curves of MAPbBr3 PSCs are obtained and the growth kinetics are theoretically modeled.Two important factors,including antisolvent vapor flux and initial precursor concentration,have been investigated experimentally for their impacts on crystal quality.By controlling the antisolvent vapor flux,the nucleation of PSCs at the container-solution interface can be regulated;while by controlling the initial precursor concentration,the crystal quality can be improved.The optimized MAPbBr3 PSCs exhibited significantly high qualities,with the narrowest reported full width at half maximum(0.00637°)of X-ray diffraction rocking curve as reported,a trap-state density as low as 2.12×10^(10 )cm^(−3),and a mobility-lifetime(μτ)product of 1.4×10^(−2) cm^(2) V^(−1).The fabricated X-ray detectors demonstrated optimal performance at an electric field of 20 V/mm,with a sensitivity of 9.02×10^(3)μC Gy^(−1) cm^(−2) and the lowest detectable dose rate of 0.08μGy s^(−1) under irradiation with continuum X-ray energy up to 20 keV.This work provides valuable insights for the development of high-quality PSCs for direct radiation detection.展开更多
We report the demonstration of a normal-incidence p-i-n germanium-tin(Ge_(0.951)Sn_(0.049))photodetector on silicon-on-insulator substrate for 2μm wavelength application.The DC and RF characteristics of the devices h...We report the demonstration of a normal-incidence p-i-n germanium-tin(Ge_(0.951)Sn_(0.049))photodetector on silicon-on-insulator substrate for 2μm wavelength application.The DC and RF characteristics of the devices have been characterized.A dark current density under−1 V bias of approximately 125 mA/cm^(2) is achieved at room temperature,and the optical responsivity of 14 mA/W is realized for illumination wavelength of 2μm under−1 V reverse bias.In addition,a 3 dB bandwidth(f_(3dB))of around 30 GHz is achieved at−3 V,which is the highest reported value among all group III–V and group IV photodetectors working in the 2μm wavelength range.This work illustrates that a GeSn photodetector has great prospects in 2μm wavelength optical communication.展开更多
A high-performance monolithic integrated wavelength division multiplexing silicon(Si) photonics receiver chip is fabricated on a silicon-on-insulator platform. The receiver chip has a 25-channel Si nanowire-arrayed wa...A high-performance monolithic integrated wavelength division multiplexing silicon(Si) photonics receiver chip is fabricated on a silicon-on-insulator platform. The receiver chip has a 25-channel Si nanowire-arrayed waveguide grating, and each channel is integrated with a high-speed waveguide Ge-on-Si photodetector. The central wavelength, optical insertion loss, and cross talk of the array waveguide grating are 1550.6 nm, 5–8 dB, and-12 –-15 dB, respectively. The photodetectors show low dark current density of 16.9 mA∕cm^2 at-1 V and a high responsivity of 0.82 A/W at 1550 nm. High bandwidths of 23 and 29 GHz are achieved at 0 and-1 V, respectively. Each channel can operate at 50 Gbps with low input optical power even under zero bias,which realizes an aggregate data rate of 1.25 Tbps.展开更多
A novel lateral Ge/Si avalanche photodiode without a charge region is investigated herein using device physical simulation. High field is provided by the band-gap barrier and build-in field at the Ge/Si interface in t...A novel lateral Ge/Si avalanche photodiode without a charge region is investigated herein using device physical simulation. High field is provided by the band-gap barrier and build-in field at the Ge/Si interface in the vertical direction. Modulating the Si mesa thickness(0-0.4 μm) and impurity concentration of the intrinsic Si substrate(1×10^(16)-4×10^(16)cm^(-3)) strengthens the electric field confinement in the substrate region and provides a high avalanche multiplication in the Si region. When the Si mesa thickness is 0.3 μm, and the impurity concentration of the Si substrate is 2×10^(16) cm^(-3), the Lateral Avalanche PhotoDiode(LAPD) exhibits a peak gain of 246 under 1.55 μm incident light power of -22.2 dBm, which increases with decreasing light intensity.展开更多
Expanding the optical communication band is one of the most effective methods of overcoming the nonlinear Shannon capacity limit of single fiber.In this study,GeSn resonance cavity enhanced(RCE)photodetectors(PDs)with...Expanding the optical communication band is one of the most effective methods of overcoming the nonlinear Shannon capacity limit of single fiber.In this study,GeSn resonance cavity enhanced(RCE)photodetectors(PDs)with an active layer Sn component of 9%–10.8%were designed and fabricated on an SOI substrate.The GeSn RCE PDs present a responsivity of 0.49 A/W at 2μm and a 3-dB bandwidth of approximately 40 GHz at 2μm.Consequently,Si-based 2μm band optical communication with a transmission rate of 50 Gbps was demonstrated by using a GeSn RCE detector.This work demonstrates the considerable potential of the Si-based 2μm band photonics in future high-speed and high-capacity optical communication.展开更多
The GeSn binary alloy is a new group IV material that exhibits a direct bandgap when the Sn content ex- ceeds 6%. It shows great potential for laser use in optoelectronic integration circuits （OEIC） on account of it...The GeSn binary alloy is a new group IV material that exhibits a direct bandgap when the Sn content ex- ceeds 6%. It shows great potential for laser use in optoelectronic integration circuits （OEIC） on account of its low light emission efficiency arising from the indirect bandgap characteristics of Si and Ge. The bandgap of GeSn can be tuned from 0.6 to 0 eV by varying the Sn content, thus making this alloy suitable for use in near-infrared and mid-infrared detectors. In this paper, the growth of the GeSn alloy is first reviewed. Subsequently, GeSn photode- tectors, light emitting diodes, and lasers are discussed. The GeSn alloy presents a promising pathway for the mono- lithic integration of Si photonic circuits by the complementary metal-oxide-semiconductor （CMOS） technology.展开更多
A horizontal p-i-n ridge waveguide emitter on a slion(100)substrate with a Gen,g1Sno.c9/Ge multi quantum-well(MQW)active layer was fabricated by molecular beam epitaxy.The device structure was designed to reduce light...A horizontal p-i-n ridge waveguide emitter on a slion(100)substrate with a Gen,g1Sno.c9/Ge multi quantum-well(MQW)active layer was fabricated by molecular beam epitaxy.The device structure was designed to reduce light absorption of metal electrodes and improve injection efficiency.Electroluminescence(EL)at a wavelength of 2160 nm was observed at room temperature.Theoretical calculations indicate that the emission peak corresponds well to the direct bandgap transition(nr-mHr).The light output power was about 2.0μW with an injection current density of 200 kA/cm^2.These results show that the horizontal GeSn/Ge MQW ridge waveguide emiters have great pros-pects for group-IV light sources.展开更多
A high-speed evanescent-coupled Ge waveguide electro-absorption modulator(EAM)with simple fabrication processes was realized on a silicon-on-insulator platform with a 220 nm top Si layer.Selectively grown Ge with a tr...A high-speed evanescent-coupled Ge waveguide electro-absorption modulator(EAM)with simple fabrication processes was realized on a silicon-on-insulator platform with a 220 nm top Si layer.Selectively grown Ge with a triangle shape was directly used for Ge waveguides of the EAM.An asymmetric p-i-n junction was designed in the Ge waveguide to provide a strong electric field for Franz-Keldysh effect.The insertion loss of the Ge EAM was 6.2 dB at 1610 nm.The EAM showed the high electro-optic bandwidth of 36 GHz at-1 V.Clear open 56 Gbps eye diagrams were observed at 1610 nm with a dynamic extinction ratio of 2.7 dB and dynamic power consumption of 45 fJ/bit for voltage swing of 3Vpp.展开更多
In recent years,Perovskite Light-Emitting Diodes(PeLEDs)have received considerable attention in academia.However,with the development of PeLEDs,commercial applications of full-color PeLED technology are largely limite...In recent years,Perovskite Light-Emitting Diodes(PeLEDs)have received considerable attention in academia.However,with the development of PeLEDs,commercial applications of full-color PeLED technology are largely limited by the progress of blue-emitting devices,due to the uncontrollably accurate composition,unstable properties,and low luminance.In this article,we add Cesium chloride(CsCl)to the quasi-two-dimensional(quasi-2D)perovskite precursor solution and achieve the relatively blue shifts of PeLED emission peak by introducing chloride ions for photoluminescence(PL)and electroluminescence(EL).We also found that the introduction of chlorine ions can make quasi-2D perovskite films thinner with smoother surface of 0.408 nm.It is interesting that the EL peaks and intensities of PeLED are adjustable under different driving voltages in high concentration chlorine-added perovskite devices,and different processes of photo-excited,photo-quenched,and photo-excited occur sequentially with the increasing driving voltage.Our work provides a path for demonstrating full-color screens in the future.展开更多
Perovskite Solar Cells(PSCs)have attracted considerable attention because of their unique features and high efficiency.However,the stability of perovskite solar cells remains to be improved.In this study,we modified t...Perovskite Solar Cells(PSCs)have attracted considerable attention because of their unique features and high efficiency.However,the stability of perovskite solar cells remains to be improved.In this study,we modified the TiO_(2)Electron Transport Layer(ETL)interface with PbCl_(2).The efficiency of the perovskite solar cells with carbon electrodes increased from 11.28%to 13.34%,and their stability obviously improved.The addition of PbCl_(2)had no effect on the morphology,crystal structure,and absorption property of the perovskite absorber layer.However,it affected the band energy level alignment of the solar cells and accelerated the electron extraction and transfer at the interface between the perovskite layer and the ETL,thus enhancing the overall photovoltaic performance.The interfacial modification of ETL with PbCl_(2)is a promising way for the potential commercialization of low-cost carbon electrode-based perovskite solar cells.展开更多
Green Perovskite Light-Emitting Diodes(PeLEDs)have attracted wide attention for full spectrum displays.However,the inferior film morphology and luminescence property of quasi-two-dimensional(quasi-2D)perovskite layers...Green Perovskite Light-Emitting Diodes(PeLEDs)have attracted wide attention for full spectrum displays.However,the inferior film morphology and luminescence property of quasi-two-dimensional(quasi-2D)perovskite layers limit the photoelectric property of the PeLEDs.In this paper,the effect of strontium(Sr)doped in quasi-2D perovskite layers is investigated to obtain a high-quality active layer.The morphologies and optical properties of Sr-doped quasi-2D perovskite films with different concentrations are studied.With the addition of strontium,more low-dimensional-layer perovskite phases(n D 2 and n D 3)appear in quasi-2D perovskite films,providing efficient intraband carrier funneling pathway and facilitating radiative recombination.The photoluminescence(PL)peak intensity of optimized Sr-doped quasi-2D perovskite layers increases 50%compared with the non-strontium counterpart.Moreover,green PeLEDs based on a Sr-doped quasi-2D perovskite layer reach a maximum luminance(Lmax)of 2943.77 cd/m^(2),which is three times of the control device.The electroluminescence(EL)peaks of Maximum External Quantum Efficiency(MEQE)and Lmax of Sr-doped PeLEDs exhibite a slight shift,indicating the excellent stability and performance of Sr-doped devices.The optimized device can continuously operate for 360 s at MEQE driving voltage,resulting in a half-lifetime of60 s,which is 3-fold greater than that of the control PeLEDs.展开更多
基金supported by National Key Research and Development Program of China(2022YFB2802400)National Natural Science Foundation of China(62250010,62090054,62274160)Youth Innovation Promotion Association of the Chinese Academy of Sciences(2021111).
文摘A silicon-based germanium(Ge)photodetector working for C and L bands is proposed in this paper.The device fea-tures a novel asymmetric PIN structure,which contributes to a more optimized electric field distribution in Ge and a shorter effective width of depleted region.Meanwhile,the optical structure is designed carefully to enhance responsivity for broad-band.Under-7 V,where the weak avalanche process happens,the responsivity of our device is 1.49 and 1.16 A/W at 1550 and 1600 nm,with bandwidth of 47.1 and 44.5 GHz,respectively.These performances demonstrate the significant application poten-tial of the device in optical communication systems.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFB2200500)the National Natural Science Foundation of China(Grant Nos.61675195,61934007,and 61974170)+1 种基金Opened Fund of the State Key Laboratory of Integrated Optoelectronics,China(Grant No.IOSKL2018KF17)Beijing Natural Science Foundation,China(Grant No.4162063)
文摘An investigation of germanium-tin(GeSn) on silicon p–i–n photodetectors with a high-quality Ge0.94 Sn0.06 absorbing layer is reported. The Ge Sn photodetector reached a responsivity as high as 0.45 A/W at the wavelength of 1550 nm and 0.12 A/W at the wavelength of 2 μm. A cycle annealing technology was applied to improve the quality of the epitaxial layer during the growth process by molecular beam epitaxy. A low dark-current density under 1 V reverse bias about 0.078 A/cm2 was achieved at room temperature. Furthermore, the Ge Sn photodetector could detect a wide spectrum region and the cutoff wavelength reached to about 2.3 μm. This work has great importance in silicon-based short-wave infrared detection.
基金supported by the National Key Research and Development Program of China(2020YFB2206103)National Natural Science Foundation of China(61975196)Youth Innovation Promotion Association Chinese Academy of Sciences(2021111)。
文摘High-performance germanium(Ge)waveguide photodetectors are designed and fabricated utilizing the inductivegain-peaking technique.With the appropriate integrated inductors,the 3-dB bandwidth of photodetectors is significantly improved owing to the inductive-gain-peaking effect without any compromises to the dark current and optical responsivity.Measured 3-dB bandwidth up to 75 GHz is realized and clear open eye diagrams at 64 Gbps are observed.In this work,the relationship between the frequency response and large signal transmission characteristics on the integrated inductors of Ge waveguide photodetectors is investigated,which indicates the high-speed performance of photodetectors using the inductive-gainpeaking technique.
基金the National Key Research and Development Program of China(Grant No.2018YFB2200500)the National Natural Science Foundation(Grant Nos.62050073,62090054,61975196).
文摘Beta-gallium oxide(β-Ga_(2)O_(3))thin films were deposited on c-plane(0001)sapphire substrates with different mis-cut angles along<>by metal-organic chemical vapor deposition(MOCVD).The structural properties and surface morphology of as-grownβ-Ga_(2)O_(3)thin films were investigated in detail.It was found that by using thin buffer layer and mis-cut substrate technology,the full width at half maximum(FWHM)of the()diffraction peak of theβ-Ga_(2)O_(3)film is decreased from 2°on c-plane(0001)Al_(2)O_(3)substrate to 0.64°on an 8°off-angled c-plane(0001)Al_(2)O_(3)substrate.The surface root-mean-square(RMS)roughness can also be improved greatly and the value is 1.27 nm for 8°off-angled c-plane(0001)Al_(2)O_(3)substrate.Room temper-ature photoluminescence(PL)was observed,which was attributed to the self-trapped excitons formed by oxygen and gallium vacancies in the film.The ultraviolet-blue PL intensity related with oxygen and gallium vacancies is decreased with the increas-ing mis-cut angle,which is in agreement with the improved crystal quality measured by high resolution X-ray diffraction(HR-XRD).The present results provide a route for growing high qualityβ-Ga_(2)O_(3)film on Al_(2)O_(3)substrate.
基金supported by the National Natural Science Foundation of China(No.61036001,51072194and 60906035)
文摘A novel structure of silicon-riched nitride(SRN)/silicon-riched oxide(SRO) is proposed and prepared using RF reactive magnetron co-sputtering. High temperature annealing of SRN/SRO multilayers leads to formation of Si nanocrystals(NC) from isolating SRN and SRO layers simultaneously, which efficiently improves carrier transport ability compared to conventional SRN/Si_3N_4 counterpart. Micro-Raman scattering analysis reveals that SRN layer has dominating number of denser and smaller Si NCs, while SRO layer has relatively less, sparser and bigger Si NCs, as confirmed by high resolution transmission electron microscopy observation. The substitute SRO layers for Si_3N_4 counterparts significantly increase the amount of Si NCs as well as crystallization ratio in SRN layers; while the average Si NC size can be well controlled by the thickness of SRN layers and the content of N, and hence an obvious stronger absorption in UV region for the novel structure can be observed in absorption spectra. The I-V characteristics show that the current of hybrid SRN/SRO system increases up to 2 orders of magnitude at 1 V and even 5 orders of magnitude at 4 V compared to that of SRN/Si_3N_4 structure. Si NCs in Si Oylayers provide a transport pathway for adjacent Si NCs in Si Nxlayers. The obvious advantage in carrier transportation suggests that SRN/SRO hybrid system could be a promising structure and platform to build Si nanostructured solar cells.
文摘Si photonics is a promising technological approach to realize a photonic integrated circuits on Si substrate with small footprint,high performance,low cost,and being highly compatible with Si complementary metal oxide semiconductor(CMOS)technology[1].Because of good compatibility of Si and the relatively high absorption coefficient in the near-infrared region,Ge waveguide photodiode on Si is almost the only option for optical receiving in Si photonic integrated circuits.For a high performance Ge photodiode,the critical parameters are optical responsivity,3-dB bandwidth,and dark current.
文摘Transistor's invention revolutionized global society by spawning electronics industry. John Bardeen is among one of the inventors of transistor. He was a genius and one of the most influential semiconductor Physicist of 20 th century who won two Nobel prizes in Physics.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2020YFB2206103)。
文摘In this work,a two-step metal organic chemical vapor deposition(MOCVD)method was applied for growingβ-Ga_(2)O_(3) film on c-plane sapphire.Optimized buffer layer growth temperature(T_(B))was found at 700℃ and theβ-Ga_(2)O_(3) film with full width at half maximum(FWHM)of 0.66°was achieved.A metal−semiconductor−metal(MSM)solar-blind photodetector(PD)was fabricated based on theβ-Ga_(2)O_(3) film.Ultrahigh responsivity of 1422 A/W@254 nm and photo-to-dark current ratio(PDCR)of 10^(6) at 10 V bias were obtained.The detectivity of 2.5×10^(15) Jones proved that the photodetector has outstanding performance in detecting weak signals.Moreover,the photodetector exhibited superior wavelength selectivity with rejection ratio(R_(250 nm)/R_(400 nm))of 105.These results indicate that the two-step method is a promising approach for preparation of high-qualityβ-Ga_(2)O_(3)films for high-performance solar-blind photodetectors.
基金National Key Research and Development Program of China(2022YFB2803100)National Natural Science Foundation of China(62090054,62274160,62404216).
文摘A GeSn nanostrip grown by the rapid melting growth method has gradient Sn content along the strip,a very attractive approach for making an infrared broad-spectrum light source.In this work,by applying the Sn content distribution strategy.
基金supported by the National Key Research and Development Program of China(No.2020YFB2206103)the Na-tional Natural Science Foundation(Nos.61975196,62274160,and 62250010)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB43020100)the Youth Innova-tion Promotion Association of the Chinese Academy of Sciences(2021111).
文摘Perovskite single crystals(PSCs)have attracted significant interest for next-generation radiation detection.However,the lack of in-depth crystal growth kinetics of PSCs limits the development of high-quality PSCs.Here,with an in-situ real-time monitoring system for MAPbBr3 PSCs growth during the antisolvent vapor-assisted crystallization(AVC)process,the growth curves of MAPbBr3 PSCs are obtained and the growth kinetics are theoretically modeled.Two important factors,including antisolvent vapor flux and initial precursor concentration,have been investigated experimentally for their impacts on crystal quality.By controlling the antisolvent vapor flux,the nucleation of PSCs at the container-solution interface can be regulated;while by controlling the initial precursor concentration,the crystal quality can be improved.The optimized MAPbBr3 PSCs exhibited significantly high qualities,with the narrowest reported full width at half maximum(0.00637°)of X-ray diffraction rocking curve as reported,a trap-state density as low as 2.12×10^(10 )cm^(−3),and a mobility-lifetime(μτ)product of 1.4×10^(−2) cm^(2) V^(−1).The fabricated X-ray detectors demonstrated optimal performance at an electric field of 20 V/mm,with a sensitivity of 9.02×10^(3)μC Gy^(−1) cm^(−2) and the lowest detectable dose rate of 0.08μGy s^(−1) under irradiation with continuum X-ray energy up to 20 keV.This work provides valuable insights for the development of high-quality PSCs for direct radiation detection.
基金National Natural Science Foundation of China(61774143,61874109,61975121,61975196)National Key Research and Development Program of China(2018YFB2200501,2019YFB2203400).
文摘We report the demonstration of a normal-incidence p-i-n germanium-tin(Ge_(0.951)Sn_(0.049))photodetector on silicon-on-insulator substrate for 2μm wavelength application.The DC and RF characteristics of the devices have been characterized.A dark current density under−1 V bias of approximately 125 mA/cm^(2) is achieved at room temperature,and the optical responsivity of 14 mA/W is realized for illumination wavelength of 2μm under−1 V reverse bias.In addition,a 3 dB bandwidth(f_(3dB))of around 30 GHz is achieved at−3 V,which is the highest reported value among all group III–V and group IV photodetectors working in the 2μm wavelength range.This work illustrates that a GeSn photodetector has great prospects in 2μm wavelength optical communication.
基金National Key Research and Development Program of China(2017YFA0206404)National Natural Science Foundation of China(NSFC)(61435013,61534005,61604146)
文摘A high-performance monolithic integrated wavelength division multiplexing silicon(Si) photonics receiver chip is fabricated on a silicon-on-insulator platform. The receiver chip has a 25-channel Si nanowire-arrayed waveguide grating, and each channel is integrated with a high-speed waveguide Ge-on-Si photodetector. The central wavelength, optical insertion loss, and cross talk of the array waveguide grating are 1550.6 nm, 5–8 dB, and-12 –-15 dB, respectively. The photodetectors show low dark current density of 16.9 mA∕cm^2 at-1 V and a high responsivity of 0.82 A/W at 1550 nm. High bandwidths of 23 and 29 GHz are achieved at 0 and-1 V, respectively. Each channel can operate at 50 Gbps with low input optical power even under zero bias,which realizes an aggregate data rate of 1.25 Tbps.
基金supported in part by the National Natural Science Foundation of China (No. 61534005)Natural Science Foundation of Beijing Municipality (No. 4162063)
文摘A novel lateral Ge/Si avalanche photodiode without a charge region is investigated herein using device physical simulation. High field is provided by the band-gap barrier and build-in field at the Ge/Si interface in the vertical direction. Modulating the Si mesa thickness(0-0.4 μm) and impurity concentration of the intrinsic Si substrate(1×10^(16)-4×10^(16)cm^(-3)) strengthens the electric field confinement in the substrate region and provides a high avalanche multiplication in the Si region. When the Si mesa thickness is 0.3 μm, and the impurity concentration of the Si substrate is 2×10^(16) cm^(-3), the Lateral Avalanche PhotoDiode(LAPD) exhibits a peak gain of 246 under 1.55 μm incident light power of -22.2 dBm, which increases with decreasing light intensity.
基金National Key Research and Development Program of China (2020YFB220613)National Natural Science Foundation of China (62090054, 62250010,62274160)+1 种基金Strategic Leading Science and Technology Project,CAS (XDB43020100)Youth Innovation Promotion Association Chinese Academy of Sciences (2021111)。
文摘Expanding the optical communication band is one of the most effective methods of overcoming the nonlinear Shannon capacity limit of single fiber.In this study,GeSn resonance cavity enhanced(RCE)photodetectors(PDs)with an active layer Sn component of 9%–10.8%were designed and fabricated on an SOI substrate.The GeSn RCE PDs present a responsivity of 0.49 A/W at 2μm and a 3-dB bandwidth of approximately 40 GHz at 2μm.Consequently,Si-based 2μm band optical communication with a transmission rate of 50 Gbps was demonstrated by using a GeSn RCE detector.This work demonstrates the considerable potential of the Si-based 2μm band photonics in future high-speed and high-capacity optical communication.
基金Project supported by the Beijing Natural Science Foundation(No.4162063)the Youth Innovation Promotion Association of CAS(No.2015091)
文摘The GeSn binary alloy is a new group IV material that exhibits a direct bandgap when the Sn content ex- ceeds 6%. It shows great potential for laser use in optoelectronic integration circuits （OEIC） on account of its low light emission efficiency arising from the indirect bandgap characteristics of Si and Ge. The bandgap of GeSn can be tuned from 0.6 to 0 eV by varying the Sn content, thus making this alloy suitable for use in near-infrared and mid-infrared detectors. In this paper, the growth of the GeSn alloy is first reviewed. Subsequently, GeSn photode- tectors, light emitting diodes, and lasers are discussed. The GeSn alloy presents a promising pathway for the mono- lithic integration of Si photonic circuits by the complementary metal-oxide-semiconductor （CMOS） technology.
基金National Key Research and Development Program(2018YFB2200103,2018YFB2200501)National Natural Science Foundation of China(61674140,61675195,61774143,61975196)Key Research Program of Frontier Sciences(QYZDY-SSW-JSC022).
文摘A horizontal p-i-n ridge waveguide emitter on a slion(100)substrate with a Gen,g1Sno.c9/Ge multi quantum-well(MQW)active layer was fabricated by molecular beam epitaxy.The device structure was designed to reduce light absorption of metal electrodes and improve injection efficiency.Electroluminescence(EL)at a wavelength of 2160 nm was observed at room temperature.Theoretical calculations indicate that the emission peak corresponds well to the direct bandgap transition(nr-mHr).The light output power was about 2.0μW with an injection current density of 200 kA/cm^2.These results show that the horizontal GeSn/Ge MQW ridge waveguide emiters have great pros-pects for group-IV light sources.
基金National Key Rcscarch and Devclopment Program of China(2017YFA0206404,2018YFB2200501)National Natural Science Foundation of China(61534005,61675195,61874109,61975196).
文摘A high-speed evanescent-coupled Ge waveguide electro-absorption modulator(EAM)with simple fabrication processes was realized on a silicon-on-insulator platform with a 220 nm top Si layer.Selectively grown Ge with a triangle shape was directly used for Ge waveguides of the EAM.An asymmetric p-i-n junction was designed in the Ge waveguide to provide a strong electric field for Franz-Keldysh effect.The insertion loss of the Ge EAM was 6.2 dB at 1610 nm.The EAM showed the high electro-optic bandwidth of 36 GHz at-1 V.Clear open 56 Gbps eye diagrams were observed at 1610 nm with a dynamic extinction ratio of 2.7 dB and dynamic power consumption of 45 fJ/bit for voltage swing of 3Vpp.
基金supported by the National Key Research and Development Program of China(No.2018YFB2200103)the National Natural Science Foundation of China(Nos.61875186 and 61975196)+2 种基金the Project of the Natural Science Foundation of Beijing(No.Z160002)the Key Research Projects of Beijing Information Science and Technology University(BISTU)(Nos.2019-22,2019-23,2019-27)the Beijing Key Laboratory for Sensors of BISTU(No.2019CGKF007)。
文摘In recent years,Perovskite Light-Emitting Diodes(PeLEDs)have received considerable attention in academia.However,with the development of PeLEDs,commercial applications of full-color PeLED technology are largely limited by the progress of blue-emitting devices,due to the uncontrollably accurate composition,unstable properties,and low luminance.In this article,we add Cesium chloride(CsCl)to the quasi-two-dimensional(quasi-2D)perovskite precursor solution and achieve the relatively blue shifts of PeLED emission peak by introducing chloride ions for photoluminescence(PL)and electroluminescence(EL).We also found that the introduction of chlorine ions can make quasi-2D perovskite films thinner with smoother surface of 0.408 nm.It is interesting that the EL peaks and intensities of PeLED are adjustable under different driving voltages in high concentration chlorine-added perovskite devices,and different processes of photo-excited,photo-quenched,and photo-excited occur sequentially with the increasing driving voltage.Our work provides a path for demonstrating full-color screens in the future.
基金supported by the National Natural Science Foundation of China(Nos.61875186,61975196,and 61674140)Chinese Academy of Sciences(CAS)The World Academy of Sciences(TWAS)(CASTWAS)scholarship。
文摘Perovskite Solar Cells(PSCs)have attracted considerable attention because of their unique features and high efficiency.However,the stability of perovskite solar cells remains to be improved.In this study,we modified the TiO_(2)Electron Transport Layer(ETL)interface with PbCl_(2).The efficiency of the perovskite solar cells with carbon electrodes increased from 11.28%to 13.34%,and their stability obviously improved.The addition of PbCl_(2)had no effect on the morphology,crystal structure,and absorption property of the perovskite absorber layer.However,it affected the band energy level alignment of the solar cells and accelerated the electron extraction and transfer at the interface between the perovskite layer and the ETL,thus enhancing the overall photovoltaic performance.The interfacial modification of ETL with PbCl_(2)is a promising way for the potential commercialization of low-cost carbon electrode-based perovskite solar cells.
基金supported by the National Natural Science Foundation of China (Nos.61875186,61975196,and 61674140)。
文摘Green Perovskite Light-Emitting Diodes(PeLEDs)have attracted wide attention for full spectrum displays.However,the inferior film morphology and luminescence property of quasi-two-dimensional(quasi-2D)perovskite layers limit the photoelectric property of the PeLEDs.In this paper,the effect of strontium(Sr)doped in quasi-2D perovskite layers is investigated to obtain a high-quality active layer.The morphologies and optical properties of Sr-doped quasi-2D perovskite films with different concentrations are studied.With the addition of strontium,more low-dimensional-layer perovskite phases(n D 2 and n D 3)appear in quasi-2D perovskite films,providing efficient intraband carrier funneling pathway and facilitating radiative recombination.The photoluminescence(PL)peak intensity of optimized Sr-doped quasi-2D perovskite layers increases 50%compared with the non-strontium counterpart.Moreover,green PeLEDs based on a Sr-doped quasi-2D perovskite layer reach a maximum luminance(Lmax)of 2943.77 cd/m^(2),which is three times of the control device.The electroluminescence(EL)peaks of Maximum External Quantum Efficiency(MEQE)and Lmax of Sr-doped PeLEDs exhibite a slight shift,indicating the excellent stability and performance of Sr-doped devices.The optimized device can continuously operate for 360 s at MEQE driving voltage,resulting in a half-lifetime of60 s,which is 3-fold greater than that of the control PeLEDs.
