Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β...Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga_(2)O_(3) MOS capacitors were fabricated with ALD deposited Al_(2)O_(3) using H_(2)O or ozone(O_(3)) as precursors. Compared with the Al_(2)O_(3) gate dielectric with H_(2)O as ALD precursor, the leakage current for the O_(3) precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al_(2)O_(3) with O_(3) as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al_(2)O_(3) with O_(3) precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al_(2)O_(3)/β-Ga_(2)O_(3)MOS capacitor using the O_(3) precursor has a low leakage current and holds potential for application in β-Ga_(2)O_(3) MOSFETs.展开更多
Doping modification is one of the most effective ways to optimize the thermoelectric properties of Bi_(2)Te_(3)-based alloys.P-type Bi_(2−x)Sb_(x)Te_(3) thermoelectric materials have been successfully prepared by dire...Doping modification is one of the most effective ways to optimize the thermoelectric properties of Bi_(2)Te_(3)-based alloys.P-type Bi_(2−x)Sb_(x)Te_(3) thermoelectric materials have been successfully prepared by direct Sb doping method.It can be found that doping Sb into Bi_(2)Te_(3) lattice array for Bi-site replacement facilitates the generation of Sb′Te anti-site defects.This anti-site defects can increase the hole concentration and optimize electrical transport properties of Bi_(2−x)Sb_(x)Te_(3) alloys.In addition,the point defects induced by mass and stress fluctuations and the Sb impurities produced during the sintering process can enhance the multi-scale phonon scattering and reduce the lattice thermal conductivity.As a result,the Bi_(0.47)Sb_(1.63)Te_(3) sample has a maximum thermoelectric figure of merit ZT of 1.04 at 350 K.It is worth noting that the bipolar effect of Bi_(2)Te_(3)-based alloys can be weakened with the increase of Sb content.The Bi_(0.44)Sb_(1.66)Te_(3) sample has a maximum average ZT value(0.93)in the temperature range of 300–500 K,indicating that direct doping of Sb can broaden the temperature range corresponding to the optimal ZT value.This work provides an idea for developing high-performance near room temperature thermoelectric materials with a wide temperature range.展开更多
Birefringent crystals play an irreplaceable role in optical systems by adjusting the polarization state of light in optical devices.This work successfully synthesized a new thiophosphate phase ofβ-Pb_(3)P_(2)S_(8)thr...Birefringent crystals play an irreplaceable role in optical systems by adjusting the polarization state of light in optical devices.This work successfully synthesized a new thiophosphate phase ofβ-Pb_(3)P_(2)S_(8)through the high-temperature solid-state spontaneous crystallization method.Different from the cubicα-Pb_(3)P_(2)S_(8),theβ-Pb_(3)P_(2)S_(8)crystallizes in the orthorhombic Pbcn space group.Notably,β-Pb_(3)P_(2)S_(8)shows a large band gap of 2.37 e V in lead-based chalcogenides,wide infrared transparent window(2.5-15μm),and excellent thermal stability.Importantly,the experimental birefringence shows the largest value of0.26@550 nm in chalcogenides,even larger than the commercialized oxide materials.The Barder charge analysis result indicates that the exceptional birefringence effect is mainly from the Pb^(2+)and S^(2-)in the[Pb S_n]polyhedrons.Meanwhile,the parallelly arranged polyhedral layers could improve the structural anisotropic.Therefore,this work supports a new method for designing chalcogenides with exceptional birefringence effect in the infrared region.展开更多
Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti...Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.展开更多
Piezoelectric effect,plasma effect and semiconductor heterostructure are important strategies for enhanced photocatalytic performance.Herein,we developed a novel heterostructure piezoelectric photocatalyst,Ag/Ag_(2)S/...Piezoelectric effect,plasma effect and semiconductor heterostructure are important strategies for enhanced photocatalytic performance.Herein,we developed a novel heterostructure piezoelectric photocatalyst,Ag/Ag_(2)S/BiFeO_(3)(AAS/BFO),for photocatalytic degradation of ciprofloxacin from water.Experimental results verified the enhancement of combining heterostructure piezoelectric polarization effect,which promotes efficient migration and separation of photogenerated carriers due to the localized surface plasmon resonance effect of Ag nanoparticles.Additionally,the introduction of Ag_(2)S constructs a new heterostructure,that enhances the electron transport rate and improves the separation efficiency on electron-hole pairs.Under ultrasonic stimulation and visible light irradiation,the degradation efficiencies of 15%-AAS/BFO towards ciprofloxacin,methyl orange and methylene blue are significantly enhanced compared to pure BFO fibers.The demonstrated AAS/BFO material based on the synergistic piezoelectric effect and plasmon heterostructure shows potential in efficient organic pollutants water treatment and transforming mechanical energy into chemical energy.展开更多
Devising S-scheme heterostructure is considered as a cutting-edge strategy for advanced photocatalysts with effectively segregated photo-carriers and prominent redox potential for emerging organic pollutants control.H...Devising S-scheme heterostructure is considered as a cutting-edge strategy for advanced photocatalysts with effectively segregated photo-carriers and prominent redox potential for emerging organic pollutants control.Herein,an S-scheme Ag_(2)CO_(3)/C_(3)N_(5) heterojunction photocatalyst was developed via a simple in situ chemical deposition procedure,and further photoreduction operation made metallic Ag(size:3.5–12.5 nm)being in situ formed on Ag_(2)CO_(3)/C_(3)N_(5) for a plasmonic S-scheme Ag/Ag_(2)CO_(3)/C_(3)N_(5) heterojunction photocatalyst.Consequently,Ag/Ag_(2)CO_(3)/C_(3)N_(5) manifests pronouncedly upgraded photocatalytic performance toward oxytetracycline degradation with a superior photoreaction rate constant of 0.0475 min‒1,which is 13.2,3.9 and 2.2 folds that of C_(3)N_(5),Ag_(2)CO_(3),and Ag_(2)CO_(3)/C_(3)N_(5),respectively.As evidenced by comprehensive characterizations and density functional theory calculations,the localized surface plasmon resonance effect of metallic Ag and the unique S-scheme charge transfer mechanism in 0D/0D/2D Ag/Ag_(2)CO_(3)/C_(3)N_(5) collaboratively strengthen the visible-light absorption,and facilitate the effective separation of powerful charge carriers,thereby significantly promoting the generation of reactive species like·OH^(-),h^(+)and·O_(2)^(-)for efficient oxytetracycline destruction.Moreover,four consecutive cycles demonstrate the reusability of Ag/Ag_(2)CO_(3)/C_(3)N_(5).Furthermore,the authentic water purification tests affirm its practical application potential.This work not only provides a candidate strategy for advancing S-scheme heterojunction photocatalysts but also makes a certain contribution to water decontamination.展开更多
The industrial implementation of Solar-driven photocatalysis is hampered by inefficient charge separation,poor reusability and hard retrieval of powdery catalysts.To conquer these drawbacks,a self-floating S-scheme Bi...The industrial implementation of Solar-driven photocatalysis is hampered by inefficient charge separation,poor reusability and hard retrieval of powdery catalysts.To conquer these drawbacks,a self-floating S-scheme Bi_(4)O_(5)Br_(2)/P-doped C_(3)N_(4)/carbon fiber cloth(BB/PN/CC)composed of carbon fibers(CC)as the core and Bi_(4)O_(5)Br_(2)/P-doped C_(3)N_(4)(BB/PN)nanosheets as the shell was constructed as a competent,recyclable cloth-shaped photocatalyst for safe and efficient degradation of aquacultural antibiotics.The BB/PN/CC fabric achieves an exceptional tetracycline degradation rate constant of 0.0118 min‒1,surpassing CN/CC(0.0015 min^(‒1)),BB/CC(0.0066 min^(‒1))and PN/CC(0.0023 min^(‒1))by 6.9,0.8 and 4.1 folds,respectively.Beyond its catalytic prowess,the photocatalyst’s practical superiority is evident in its effortless recovery and environmental adaptability.The superior catalytic effectiveness stems from the S-scheme configuration,which retains the maximum redox capacities of the constituent BB and PN while enabling efficient spatial detachment of photo-carriers.X-ray photoelectron spectroscopy(XPS),in-situ XPS,and electron paramagnetic resonance analyses corroborate the S-scheme mechanism,revealing electron accumulation on PN and hole retention on BB under illumination.Density functional theory calculations further confirm S-scheme interfacial charge redistribution and internal electric field formation.This study advances the design of macroscopic S-scheme heterojunction photocatalysts for sustainable water purification.展开更多
基金Project supported in part by the Science and Technology Development Plan Project of Jilin Province, China (Grant No. YDZJ202303CGZH022)the National Key Research and Development Program of China (Grant No. 2024YFE0205300)+1 种基金the National Natural Science Foundation of China (Grant No. 62471504)the Open Fund of the State Key Laboratory of Optoelectronic Materials and Technologies (Sun Yat-Sen University) (Grant No. OEMT-2023KF-05)。
文摘Metal–insulator–semiconductor(MOS) capacitor is a key structure for high performance MOS field transistors(MOSFETs), requiring low leakage current, high breakdown voltage, and low interface states. In this paper, β-Ga_(2)O_(3) MOS capacitors were fabricated with ALD deposited Al_(2)O_(3) using H_(2)O or ozone(O_(3)) as precursors. Compared with the Al_(2)O_(3) gate dielectric with H_(2)O as ALD precursor, the leakage current for the O_(3) precursor case is decreased by two orders of magnitude, while it keeps the same level at the fixed charges, interface state density, and border traps. The SIMS tests show that Al_(2)O_(3) with O_(3) as precursor contains more carbon impurities. The current transport mechanism analysis suggests that the C–H complex in Al_(2)O_(3) with O_(3) precursor serves as deep energy trap to reduce the leakage current. These results indicate that the Al_(2)O_(3)/β-Ga_(2)O_(3)MOS capacitor using the O_(3) precursor has a low leakage current and holds potential for application in β-Ga_(2)O_(3) MOSFETs.
基金supported by the Anhui Province Natural Science Foundation for Excellent Youth Scholars(2208085Y17)the University Synergy Innovation Program of Anhui Province(GXXT-2022-008+1 种基金GXXT-2021-022)the Anhui Key Lab of Metal Material and Processing Open Project.
文摘Doping modification is one of the most effective ways to optimize the thermoelectric properties of Bi_(2)Te_(3)-based alloys.P-type Bi_(2−x)Sb_(x)Te_(3) thermoelectric materials have been successfully prepared by direct Sb doping method.It can be found that doping Sb into Bi_(2)Te_(3) lattice array for Bi-site replacement facilitates the generation of Sb′Te anti-site defects.This anti-site defects can increase the hole concentration and optimize electrical transport properties of Bi_(2−x)Sb_(x)Te_(3) alloys.In addition,the point defects induced by mass and stress fluctuations and the Sb impurities produced during the sintering process can enhance the multi-scale phonon scattering and reduce the lattice thermal conductivity.As a result,the Bi_(0.47)Sb_(1.63)Te_(3) sample has a maximum thermoelectric figure of merit ZT of 1.04 at 350 K.It is worth noting that the bipolar effect of Bi_(2)Te_(3)-based alloys can be weakened with the increase of Sb content.The Bi_(0.44)Sb_(1.66)Te_(3) sample has a maximum average ZT value(0.93)in the temperature range of 300–500 K,indicating that direct doping of Sb can broaden the temperature range corresponding to the optimal ZT value.This work provides an idea for developing high-performance near room temperature thermoelectric materials with a wide temperature range.
基金supported in part by the National Natural Science Foundation of China(No.52102218)the National Key Research and Development Program of China(No.2020YFA0710303)+2 种基金the Fujian Science&Technology Innovation Laboratory for Op-toelectronic Information of China(No.2021ZZ127)the Minjiang Scholar Professorship(No.GXRC-21004)the Natural Science Foundation of Fujian Province of China(No.2021J01594)。
文摘Birefringent crystals play an irreplaceable role in optical systems by adjusting the polarization state of light in optical devices.This work successfully synthesized a new thiophosphate phase ofβ-Pb_(3)P_(2)S_(8)through the high-temperature solid-state spontaneous crystallization method.Different from the cubicα-Pb_(3)P_(2)S_(8),theβ-Pb_(3)P_(2)S_(8)crystallizes in the orthorhombic Pbcn space group.Notably,β-Pb_(3)P_(2)S_(8)shows a large band gap of 2.37 e V in lead-based chalcogenides,wide infrared transparent window(2.5-15μm),and excellent thermal stability.Importantly,the experimental birefringence shows the largest value of0.26@550 nm in chalcogenides,even larger than the commercialized oxide materials.The Barder charge analysis result indicates that the exceptional birefringence effect is mainly from the Pb^(2+)and S^(2-)in the[Pb S_n]polyhedrons.Meanwhile,the parallelly arranged polyhedral layers could improve the structural anisotropic.Therefore,this work supports a new method for designing chalcogenides with exceptional birefringence effect in the infrared region.
基金the National Key R&D Program of China(No.2023YFB3210102).
文摘Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.
基金supported by the National Natural Science Foundation of China(Nos.52372090 and 52073177)the National Natural Science Foundation of Guangdong,China(No.2023A1515010947)Shenzhen Basic Research Program(No.JCYJ20220531102207017).
文摘Piezoelectric effect,plasma effect and semiconductor heterostructure are important strategies for enhanced photocatalytic performance.Herein,we developed a novel heterostructure piezoelectric photocatalyst,Ag/Ag_(2)S/BiFeO_(3)(AAS/BFO),for photocatalytic degradation of ciprofloxacin from water.Experimental results verified the enhancement of combining heterostructure piezoelectric polarization effect,which promotes efficient migration and separation of photogenerated carriers due to the localized surface plasmon resonance effect of Ag nanoparticles.Additionally,the introduction of Ag_(2)S constructs a new heterostructure,that enhances the electron transport rate and improves the separation efficiency on electron-hole pairs.Under ultrasonic stimulation and visible light irradiation,the degradation efficiencies of 15%-AAS/BFO towards ciprofloxacin,methyl orange and methylene blue are significantly enhanced compared to pure BFO fibers.The demonstrated AAS/BFO material based on the synergistic piezoelectric effect and plasmon heterostructure shows potential in efficient organic pollutants water treatment and transforming mechanical energy into chemical energy.
文摘Devising S-scheme heterostructure is considered as a cutting-edge strategy for advanced photocatalysts with effectively segregated photo-carriers and prominent redox potential for emerging organic pollutants control.Herein,an S-scheme Ag_(2)CO_(3)/C_(3)N_(5) heterojunction photocatalyst was developed via a simple in situ chemical deposition procedure,and further photoreduction operation made metallic Ag(size:3.5–12.5 nm)being in situ formed on Ag_(2)CO_(3)/C_(3)N_(5) for a plasmonic S-scheme Ag/Ag_(2)CO_(3)/C_(3)N_(5) heterojunction photocatalyst.Consequently,Ag/Ag_(2)CO_(3)/C_(3)N_(5) manifests pronouncedly upgraded photocatalytic performance toward oxytetracycline degradation with a superior photoreaction rate constant of 0.0475 min‒1,which is 13.2,3.9 and 2.2 folds that of C_(3)N_(5),Ag_(2)CO_(3),and Ag_(2)CO_(3)/C_(3)N_(5),respectively.As evidenced by comprehensive characterizations and density functional theory calculations,the localized surface plasmon resonance effect of metallic Ag and the unique S-scheme charge transfer mechanism in 0D/0D/2D Ag/Ag_(2)CO_(3)/C_(3)N_(5) collaboratively strengthen the visible-light absorption,and facilitate the effective separation of powerful charge carriers,thereby significantly promoting the generation of reactive species like·OH^(-),h^(+)and·O_(2)^(-)for efficient oxytetracycline destruction.Moreover,four consecutive cycles demonstrate the reusability of Ag/Ag_(2)CO_(3)/C_(3)N_(5).Furthermore,the authentic water purification tests affirm its practical application potential.This work not only provides a candidate strategy for advancing S-scheme heterojunction photocatalysts but also makes a certain contribution to water decontamination.
文摘The industrial implementation of Solar-driven photocatalysis is hampered by inefficient charge separation,poor reusability and hard retrieval of powdery catalysts.To conquer these drawbacks,a self-floating S-scheme Bi_(4)O_(5)Br_(2)/P-doped C_(3)N_(4)/carbon fiber cloth(BB/PN/CC)composed of carbon fibers(CC)as the core and Bi_(4)O_(5)Br_(2)/P-doped C_(3)N_(4)(BB/PN)nanosheets as the shell was constructed as a competent,recyclable cloth-shaped photocatalyst for safe and efficient degradation of aquacultural antibiotics.The BB/PN/CC fabric achieves an exceptional tetracycline degradation rate constant of 0.0118 min‒1,surpassing CN/CC(0.0015 min^(‒1)),BB/CC(0.0066 min^(‒1))and PN/CC(0.0023 min^(‒1))by 6.9,0.8 and 4.1 folds,respectively.Beyond its catalytic prowess,the photocatalyst’s practical superiority is evident in its effortless recovery and environmental adaptability.The superior catalytic effectiveness stems from the S-scheme configuration,which retains the maximum redox capacities of the constituent BB and PN while enabling efficient spatial detachment of photo-carriers.X-ray photoelectron spectroscopy(XPS),in-situ XPS,and electron paramagnetic resonance analyses corroborate the S-scheme mechanism,revealing electron accumulation on PN and hole retention on BB under illumination.Density functional theory calculations further confirm S-scheme interfacial charge redistribution and internal electric field formation.This study advances the design of macroscopic S-scheme heterojunction photocatalysts for sustainable water purification.
