The high critical electric field strength of Ga_(2)O_(3)enables higher operating voltages and reduced switching losses in power electronic devices.Suitable Schottky metals and epitaxial films are essential for further...The high critical electric field strength of Ga_(2)O_(3)enables higher operating voltages and reduced switching losses in power electronic devices.Suitable Schottky metals and epitaxial films are essential for further enhancing device performance.In this work,the fabrication of vertical Ga_(2)O_(3)barrier diodes with three different barrier metals was carried out on an n--Ga_(2)O_(3)homogeneous epitaxial film deposited on an n+-β-Ga_(2)O_(3)substrate by metal-organic chemical vapor deposition,excluding the use of edge terminals.The ideal factor,barrier height,specific on-resistance,and breakdown voltage characteristics of all devices were investigated at room temperature.In addition,the vertical Ga_(2)O_(3)barrier diodes achieve a higher breakdown volt-age and exhibit a reverse leakage as low as 4.82×10^(-8)A/cm^(2)by constructing a NiO/Ga_(2)O_(3)heterojunction.Therefore,Ga_(2)O_(3)power detailed investigations into Schottky barrier metal and NiO/Ga_(2)O_(3)heterojunction of Ga_(2)O_(3)homogeneous epitaxial films are of great research potential in high-efficiency,high-power,and high-reliability applications.展开更多
In this work,a PEDOT:PSS/Sn:α-Ga_(2)O_(3) hybrid heterojunction diode(HJD)photodetector was fabricated by spin-coat-ing highly conductive PEDOT:PSS aqueous solution on the mist chemical vapor deposition(Mist-CVD)grow...In this work,a PEDOT:PSS/Sn:α-Ga_(2)O_(3) hybrid heterojunction diode(HJD)photodetector was fabricated by spin-coat-ing highly conductive PEDOT:PSS aqueous solution on the mist chemical vapor deposition(Mist-CVD)grown Sn:α-Ga_(2)O_(3) film.This approach provides a facile and low-cost p-PEDOT:PSS/n-Sn:α-Ga_(2)O_(3) spin-coating method that facilitates self-powering per-formance through p-n junction formation.A typical type-Ⅰheterojunction is formed at the interface of Sn:α-Ga_(2)O_(3) film and PEDOT:PSS,and contributes to a significant photovoltaic effect with an open-circuit voltage(Voc)of 0.4 V under the 254 nm ultra-violet(UV)light.When operating in self-powered mode,the HJD exhibits excellent photo-response performance including an outstanding photo-current of 10.9 nA,a rapid rise/decay time of 0.38/0.28 s,and a large on/off ratio of 91.2.Additionally,the HJD also possesses excellent photo-detection performance with a high responsivity of 5.61 mA/W and a good detectivity of 1.15×1011 Jones at 0 V bias under 254 nm UV light illumination.Overall,this work may explore the potential range of self-pow-ered and high-performance UV photodetectors.展开更多
Beta gallium oxide(β-Ga_(2)O_(3)) has attracted significant attention for applications in power electronics due to its ultrawide bandgap of ~ 4.8 eV and the large critical electric field of 8 MV/cm. These properties ...Beta gallium oxide(β-Ga_(2)O_(3)) has attracted significant attention for applications in power electronics due to its ultrawide bandgap of ~ 4.8 eV and the large critical electric field of 8 MV/cm. These properties yield a high Baliga's figures of merit(BFOM) of more than 3000. Though β-Ga_(2)O_(3) possesses superior material properties, the lack of p-type doping is the main obstacle that hinders the development of β-Ga_(2)O_(3)-based power devices for commercial use. Constructing heterojunctions by employing other p-type materials has been proven to be a feasible solution to this issue. Nickel oxide(NiO) is the most promising candidate due to its wide band gap of 3.6–4.0 eV. So far, remarkable progress has been made in NiO/β-Ga_(2)O_(3) heterojunction power devices. This review aims to summarize recent advances in the construction, characterization, and device performance of the NiO/β-Ga_(2)O_(3) heterojunction power devices. The crystallinity, band structure, and carrier transport property of the sputtered NiO/β-Ga_(2)O_(3) heterojunctions are discussed. Various device architectures, including the NiO/β-Ga_(2)O_(3) heterojunction pn diodes(HJDs), junction barrier Schottky(JBS) diodes, and junction field effect transistors(JFET), as well as the edge terminations and super-junctions based on the NiO/β-Ga_(2)O_(3) heterojunction, are described.展开更多
A NiO/β-Ga_(2)O_(3) heterojunction-gate field effect transistor(HJ-FET)is fabricated and it_(s)instability mechanisms are exper-imentally investigated under different gate stress voltage(V_(G,s))and stress times(t_(s...A NiO/β-Ga_(2)O_(3) heterojunction-gate field effect transistor(HJ-FET)is fabricated and it_(s)instability mechanisms are exper-imentally investigated under different gate stress voltage(V_(G,s))and stress times(t_(s)).Two different degradation mechanisms of the devices under negative bias stress(NBS)are identified.At low V_(G,s)for a short t_(s),NiO bulk traps trapping/de-trapping elec-trons are responsible for decrease/recovery of the leakage current,respectively.At higher V_(G,s)or long t_(s),the device transfer char-acteristic curves and threshold voltage(V_(TH))are almost permanently negatively shifted.This is because the interface dipoles are almost permanently ionized and neutralize the ionized charges in the space charge region(SCR)across the heterojunction inter-face,resulting in a narrowing SCR.This provides an important theoretical guide to study the reliability of NiO/β-Ga_(2)O_(3) hetero-junction devices in power electronic applications.展开更多
The 10 nm p-NiO thin film is prepared by thermal oxidation of Ni onβ-Ga_(2)O_(3)to form NiO/β-Ga_(2)O_(3)p-n heterojunction diodes(HJDs).The NiO/β-Ga_(2)O_(3)HJDs exhibit excellent electrostatic properties,with a h...The 10 nm p-NiO thin film is prepared by thermal oxidation of Ni onβ-Ga_(2)O_(3)to form NiO/β-Ga_(2)O_(3)p-n heterojunction diodes(HJDs).The NiO/β-Ga_(2)O_(3)HJDs exhibit excellent electrostatic properties,with a high breakdown voltage of 465 V,a specific on-resistance(Ron,sp)of 3.39 mΩ·cm^(2),and a turn-on voltage(V on)of 1.85 V,yielding a static Baliga's figure of merit(FOM)of 256 MW/cm^(2).Also,the HJDs have a low turn-on voltage,which reduces conduction loss dramatically,and a rectification ratio of up to 108.Meanwhile,the HJDs'reverse leakage current is essentially unaffected at temperatures below 170?C,and their leakage level may be controlled below 10^(-10)A.This indicates that p-NiO/β-Ga_(2)O_(3)HJDs with good thermal stability and high-temperature operating ability can be a good option for high-performanceβ-Ga_(2)O_(3)power devices.展开更多
This work demonstrates high-performance NiO/β-Ga_(2)O_(3) vertical heterojunction diodes(HJDs)with double-layer junc-tion termination extension(DL-JTE)consisting of two p-typed NiO layers with varied lengths.The bott...This work demonstrates high-performance NiO/β-Ga_(2)O_(3) vertical heterojunction diodes(HJDs)with double-layer junc-tion termination extension(DL-JTE)consisting of two p-typed NiO layers with varied lengths.The bottom 60-nm p-NiO layer fully covers theβ-Ga_(2)O_(3) wafer,while the geometry of the upper 60-nm p-NiO layer is 10μm larger than the square anode elec-trode.Compared with a single-layer JTE,the electric field concentration is inhibited by double-layer JTE structure effectively,resulting in the breakdown voltage being improved from 2020 to 2830 V.Moreover,double p-typed NiO layers allow more holes into the Ga_(2)O_(3) drift layer to reduce drift resistance.The specific on-resistance is reduced from 1.93 to 1.34 mΩ·cm^(2).The device with DL-JTE shows a power figure-of-merit(PFOM)of 5.98 GW/cm^(2),which is 2.8 times larger than that of the conven-tional single-layer JTE structure.These results indicate that the double-layer JTE structure provides a viable way of fabricating high-performance Ga_(2)O_(3) HJDs.展开更多
A self-powered solar-blind ultraviolet(UV)photodetector(PD)was successfully constructed on a Ga_(2)O_(3)/Bi_(2)WO_(6)heterojunction,which was fabricated by spin-coating the hydrothermally grown Bi_(2)WO_(6)onto MOCVD-...A self-powered solar-blind ultraviolet(UV)photodetector(PD)was successfully constructed on a Ga_(2)O_(3)/Bi_(2)WO_(6)heterojunction,which was fabricated by spin-coating the hydrothermally grown Bi_(2)WO_(6)onto MOCVD-grown Ga_(2)O_(3)film.The results show that a typical type-I heterojunction is formed at the interface of the Ga_(2)O_(3)film and clustered Bi_(2)WO_(6),which demonstrates a distinct photovoltaic effect with an open-circuit voltage of 0.18 V under the irradiation of 254 nm UV light.Moreover,the Ga_(2)O_(3)/Bi_(2)WO_(6)PD displays excellent photodetection performance with an ultra-low dark current of~6 fA,and a high light-to-dark current ratio(PDCR)of 3.5 x 10^(4)in self-powered mode(0 V),as well as a best responsivity result of 2.21 mA/W in power supply mode(5 V).Furthermore,the PD possesses a stable and fast response speed under different light intensities and voltages.At zero voltage,the PD exhibits a fast rise time of 132 ms and 162 ms,as well as a quick decay time of 69 ms and 522 ms,respectively.In general,the newly attempted Ga_(2)O_(3)/Bi_(2)WO_(6)heterojunction may become a potential candidate for the realization of self-powered and high-performance UV photodetectors.展开更多
基金supported by BUPT Excellent Ph.D. Students Foundation (CX2023301)in part by the National Natural Science Foundation of China (62204019)
文摘The high critical electric field strength of Ga_(2)O_(3)enables higher operating voltages and reduced switching losses in power electronic devices.Suitable Schottky metals and epitaxial films are essential for further enhancing device performance.In this work,the fabrication of vertical Ga_(2)O_(3)barrier diodes with three different barrier metals was carried out on an n--Ga_(2)O_(3)homogeneous epitaxial film deposited on an n+-β-Ga_(2)O_(3)substrate by metal-organic chemical vapor deposition,excluding the use of edge terminals.The ideal factor,barrier height,specific on-resistance,and breakdown voltage characteristics of all devices were investigated at room temperature.In addition,the vertical Ga_(2)O_(3)barrier diodes achieve a higher breakdown volt-age and exhibit a reverse leakage as low as 4.82×10^(-8)A/cm^(2)by constructing a NiO/Ga_(2)O_(3)heterojunction.Therefore,Ga_(2)O_(3)power detailed investigations into Schottky barrier metal and NiO/Ga_(2)O_(3)heterojunction of Ga_(2)O_(3)homogeneous epitaxial films are of great research potential in high-efficiency,high-power,and high-reliability applications.
基金supported by the National Key Research and Development Program of China (Grant No.2022YFB3605404)the Young Scientists Fund of the National Natural Science Foundation of China (Grant Nos.62204125,62305171,62204126,and 62304113)+3 种基金the Joints Fund of the National Natural Science Foundation of China (Grant No.U23A20349)the Natural Science Foundation of Jiangsu Province (Grant No.BK20230361)the Natural Science Research Startup Foundation of Recuring Talents of Nanjing University of Posts and Telecommunications (Grant No.XK1060921119)the Jiangsu Provincial Team of Innovation and Entrepreneurship (Grant No.JSSCTD202351).
文摘In this work,a PEDOT:PSS/Sn:α-Ga_(2)O_(3) hybrid heterojunction diode(HJD)photodetector was fabricated by spin-coat-ing highly conductive PEDOT:PSS aqueous solution on the mist chemical vapor deposition(Mist-CVD)grown Sn:α-Ga_(2)O_(3) film.This approach provides a facile and low-cost p-PEDOT:PSS/n-Sn:α-Ga_(2)O_(3) spin-coating method that facilitates self-powering per-formance through p-n junction formation.A typical type-Ⅰheterojunction is formed at the interface of Sn:α-Ga_(2)O_(3) film and PEDOT:PSS,and contributes to a significant photovoltaic effect with an open-circuit voltage(Voc)of 0.4 V under the 254 nm ultra-violet(UV)light.When operating in self-powered mode,the HJD exhibits excellent photo-response performance including an outstanding photo-current of 10.9 nA,a rapid rise/decay time of 0.38/0.28 s,and a large on/off ratio of 91.2.Additionally,the HJD also possesses excellent photo-detection performance with a high responsivity of 5.61 mA/W and a good detectivity of 1.15×1011 Jones at 0 V bias under 254 nm UV light illumination.Overall,this work may explore the potential range of self-pow-ered and high-performance UV photodetectors.
基金supported by the Guangdong Basic and Applied Basic Research Foundation under Grant No. 2022A1515012163。
文摘Beta gallium oxide(β-Ga_(2)O_(3)) has attracted significant attention for applications in power electronics due to its ultrawide bandgap of ~ 4.8 eV and the large critical electric field of 8 MV/cm. These properties yield a high Baliga's figures of merit(BFOM) of more than 3000. Though β-Ga_(2)O_(3) possesses superior material properties, the lack of p-type doping is the main obstacle that hinders the development of β-Ga_(2)O_(3)-based power devices for commercial use. Constructing heterojunctions by employing other p-type materials has been proven to be a feasible solution to this issue. Nickel oxide(NiO) is the most promising candidate due to its wide band gap of 3.6–4.0 eV. So far, remarkable progress has been made in NiO/β-Ga_(2)O_(3) heterojunction power devices. This review aims to summarize recent advances in the construction, characterization, and device performance of the NiO/β-Ga_(2)O_(3) heterojunction power devices. The crystallinity, band structure, and carrier transport property of the sputtered NiO/β-Ga_(2)O_(3) heterojunctions are discussed. Various device architectures, including the NiO/β-Ga_(2)O_(3) heterojunction pn diodes(HJDs), junction barrier Schottky(JBS) diodes, and junction field effect transistors(JFET), as well as the edge terminations and super-junctions based on the NiO/β-Ga_(2)O_(3) heterojunction, are described.
基金supported by the Fundamental Strengthening Program Key Basic Research Project(Grant No.2021-173ZD-057).
文摘A NiO/β-Ga_(2)O_(3) heterojunction-gate field effect transistor(HJ-FET)is fabricated and it_(s)instability mechanisms are exper-imentally investigated under different gate stress voltage(V_(G,s))and stress times(t_(s)).Two different degradation mechanisms of the devices under negative bias stress(NBS)are identified.At low V_(G,s)for a short t_(s),NiO bulk traps trapping/de-trapping elec-trons are responsible for decrease/recovery of the leakage current,respectively.At higher V_(G,s)or long t_(s),the device transfer char-acteristic curves and threshold voltage(V_(TH))are almost permanently negatively shifted.This is because the interface dipoles are almost permanently ionized and neutralize the ionized charges in the space charge region(SCR)across the heterojunction inter-face,resulting in a narrowing SCR.This provides an important theoretical guide to study the reliability of NiO/β-Ga_(2)O_(3) hetero-junction devices in power electronic applications.
基金the Technology Innovation and Application Demonstration Key Project of Chongqing Municipality(cstc2019jszx-zdztzxX0005)the Technology Innovation and Application Demonstration Key Project of Chongqing Municipality(cstc2020jscx-gksbX0011)+1 种基金the Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202100614)the Natural Science Foundation of Chongqing(cstc2021jcyj-bshX0146)。
文摘The 10 nm p-NiO thin film is prepared by thermal oxidation of Ni onβ-Ga_(2)O_(3)to form NiO/β-Ga_(2)O_(3)p-n heterojunction diodes(HJDs).The NiO/β-Ga_(2)O_(3)HJDs exhibit excellent electrostatic properties,with a high breakdown voltage of 465 V,a specific on-resistance(Ron,sp)of 3.39 mΩ·cm^(2),and a turn-on voltage(V on)of 1.85 V,yielding a static Baliga's figure of merit(FOM)of 256 MW/cm^(2).Also,the HJDs have a low turn-on voltage,which reduces conduction loss dramatically,and a rectification ratio of up to 108.Meanwhile,the HJDs'reverse leakage current is essentially unaffected at temperatures below 170?C,and their leakage level may be controlled below 10^(-10)A.This indicates that p-NiO/β-Ga_(2)O_(3)HJDs with good thermal stability and high-temperature operating ability can be a good option for high-performanceβ-Ga_(2)O_(3)power devices.
基金supported by the National Natural Science Foundation of China under Grant U21A20503.
文摘This work demonstrates high-performance NiO/β-Ga_(2)O_(3) vertical heterojunction diodes(HJDs)with double-layer junc-tion termination extension(DL-JTE)consisting of two p-typed NiO layers with varied lengths.The bottom 60-nm p-NiO layer fully covers theβ-Ga_(2)O_(3) wafer,while the geometry of the upper 60-nm p-NiO layer is 10μm larger than the square anode elec-trode.Compared with a single-layer JTE,the electric field concentration is inhibited by double-layer JTE structure effectively,resulting in the breakdown voltage being improved from 2020 to 2830 V.Moreover,double p-typed NiO layers allow more holes into the Ga_(2)O_(3) drift layer to reduce drift resistance.The specific on-resistance is reduced from 1.93 to 1.34 mΩ·cm^(2).The device with DL-JTE shows a power figure-of-merit(PFOM)of 5.98 GW/cm^(2),which is 2.8 times larger than that of the conven-tional single-layer JTE structure.These results indicate that the double-layer JTE structure provides a viable way of fabricating high-performance Ga_(2)O_(3) HJDs.
基金Project supported by the National Key Research and Development Program of China(Grant No.2022YFB3605404)Natural Science Research Start up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(Grant Nos.XK1060921119,XK1060921115,and XK1060921002)+1 种基金National Natural Science Foundation of China(Grant No.62204125)China Postdoctoral Science Foundation(Grant No.2022M721689)。
文摘A self-powered solar-blind ultraviolet(UV)photodetector(PD)was successfully constructed on a Ga_(2)O_(3)/Bi_(2)WO_(6)heterojunction,which was fabricated by spin-coating the hydrothermally grown Bi_(2)WO_(6)onto MOCVD-grown Ga_(2)O_(3)film.The results show that a typical type-I heterojunction is formed at the interface of the Ga_(2)O_(3)film and clustered Bi_(2)WO_(6),which demonstrates a distinct photovoltaic effect with an open-circuit voltage of 0.18 V under the irradiation of 254 nm UV light.Moreover,the Ga_(2)O_(3)/Bi_(2)WO_(6)PD displays excellent photodetection performance with an ultra-low dark current of~6 fA,and a high light-to-dark current ratio(PDCR)of 3.5 x 10^(4)in self-powered mode(0 V),as well as a best responsivity result of 2.21 mA/W in power supply mode(5 V).Furthermore,the PD possesses a stable and fast response speed under different light intensities and voltages.At zero voltage,the PD exhibits a fast rise time of 132 ms and 162 ms,as well as a quick decay time of 69 ms and 522 ms,respectively.In general,the newly attempted Ga_(2)O_(3)/Bi_(2)WO_(6)heterojunction may become a potential candidate for the realization of self-powered and high-performance UV photodetectors.
