The growth of AlGaAsSb quatornary alloys is described. In order to control the epimxial growth ofAIGaAsSb, emphasis is given on the deposition rates, growth temperatures and the relationship between growthconditions a...The growth of AlGaAsSb quatornary alloys is described. In order to control the epimxial growth ofAIGaAsSb, emphasis is given on the deposition rates, growth temperatures and the relationship between growthconditions and the distribution coefficients of Al and As. Whether the growth of AlGaAsSb epilayers is con-trolled by chemical reactions or by mass diffusion depends on the growth temperatures. This argument is veri-fied by kinetic considerations. Specular surfaces of AlGaAsSb on GaSb substrates were obtained. The composi-tional nonuniformities measured by electron probe micro-analysis (EPMA) are less than 0. 6% on area of 15× 15 mm￣2. The crystallinity is measured by double crystal X-ray diffraction (DCXD). The lattice mismatchbetween AlGaAsSb epilayer and GaSb subetrato is estimated to be less than 5. 5 × 10￣(-4).展开更多
In this study,the high performance of InGaN/GaN multiple quantum well light-emitting diodes（LEDs） with Aldoped ZnO（AZO） transparent conductive layers（TCLs） has been demonstrated.The AZO-TCLs were fabricated on t...In this study,the high performance of InGaN/GaN multiple quantum well light-emitting diodes（LEDs） with Aldoped ZnO（AZO） transparent conductive layers（TCLs） has been demonstrated.The AZO-TCLs were fabricated on the n-＋-InGaN contact layer by metal organic chemical vapor deposition（MOCVD） using H2O as an oxidizer at temperatures as low as 400 ℃ without any post-deposition annealing.It shows a high transparency（98%）,low resistivity（510 -4 Ω·cm）,and an epitaxial-like excellent interface on p-GaN with an n＋-InGaN contact layer.A forward voltage of 2.82 V @ 20 mA was obtained.Most importantly,the power efficiencies can be markedly improved by 53.8%@20 mA current injection and 39.6%@350 mA current injection compared with conventional LEDs with indium tin oxide TCL（LED-Ⅲ）,and by28.8%@20 mA current injection and 4.92%@350 mA current injection compared with LEDs with AZO-TCL prepared by MOCVD using O2 as an oxidizer（LED-Ⅱ）,respectively.The results indicate that the AZO-TCL grown by MOCVD using H2O as an oxidizer is a promising TCL for a low-cost and high-efficiency GaN-based LED application.展开更多
Microstructure and misfit dislocation behavior in In_xGa_(1-x)As/InP heteroepitaxial materials grown by low pressure metal organic chemical vapor deposition(LP-MOCVD) were analyzed by high resolution transmission elec...Microstructure and misfit dislocation behavior in In_xGa_(1-x)As/InP heteroepitaxial materials grown by low pressure metal organic chemical vapor deposition(LP-MOCVD) were analyzed by high resolution transmission electron microscopy(HRTEM), scanning electron microscopy(SEM), atomic force microscopy(AFM), Raman spectroscopy and Hall effect measurements. To optimize the structure of In_(0.82)Ga_(0.18)As/InP heterostructure, the In_xGa_(1-x)As buffer layer was grown. The residual strain of the In_(0.82)Ga_(0.18)As epitaxial layer was calculated. Further, the periodic growth pattern of the misfit dislocation at the interface was discovered and verified. Then the effects of misfit dislocation on the surface morphology and microstructure of the material were studied. It is found that the misfit dislocation of high indium(In) content In_(0.82)Ga_(0.18)As epitaxial layer has significant influence on the carrier concentration.展开更多
In this work,a novel ultraviolet(UV)photodetector(PD)based on AlGaN/u-GaN/p-GaN/u-GaN heterojunction high electron mobility transistor(HEMT)has been developed.This HEMT epilayer is grown using the metal-organic chemic...In this work,a novel ultraviolet(UV)photodetector(PD)based on AlGaN/u-GaN/p-GaN/u-GaN heterojunction high electron mobility transistor(HEMT)has been developed.This HEMT epilayer is grown using the metal-organic chemical vapor deposition(MOCVD)technique,and the growth parameters,including the AlGaN growth temperature,preheating temperature of the p-GaN layer,and NH3/N2 flow rate,are optimized to improve the quality of the epilayer.The optimized epilayer exhibits a flat surface with a root mean square value of 0.146 nm and low dislocation density.The p-GaN thickness in epitaxial wafers has a significant influence on electrical and UV photoresponse.With a p-GaN of 1µm,the UV PD demonstrates a significant switching ratio and transconductance of 107 and 127.3 mS mm^(-1),respectively.Acting as a UV PD,it also exhibits a high light on/off ratio(I_(light)/I_(dark))of 6.35×10^(5),a high responsivity(R)of 48.11 A W^(-1),and a detectivity(D*)of 6.85×10^(12)Jones under 365-nm UV illumination with light power density of 86.972 mW cm^(-2).The high-performance HEMT and UV detectors,which incorporate p-GaN etchless technology,have been refined through advancements in epitaxial growth and structural design.These improvements solidify the groundwork for large-scale manufacturing of UV communication systems and laser diodes.展开更多
文摘The growth of AlGaAsSb quatornary alloys is described. In order to control the epimxial growth ofAIGaAsSb, emphasis is given on the deposition rates, growth temperatures and the relationship between growthconditions and the distribution coefficients of Al and As. Whether the growth of AlGaAsSb epilayers is con-trolled by chemical reactions or by mass diffusion depends on the growth temperatures. This argument is veri-fied by kinetic considerations. Specular surfaces of AlGaAsSb on GaSb substrates were obtained. The composi-tional nonuniformities measured by electron probe micro-analysis (EPMA) are less than 0. 6% on area of 15× 15 mm￣2. The crystallinity is measured by double crystal X-ray diffraction (DCXD). The lattice mismatchbetween AlGaAsSb epilayer and GaSb subetrato is estimated to be less than 5. 5 × 10￣(-4).
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61204091,61404177,51402366,and U1201254)the Science and Technology Planning Project of Guangdong Province,China(Grant No.2015B010132006)
文摘In this study,the high performance of InGaN/GaN multiple quantum well light-emitting diodes（LEDs） with Aldoped ZnO（AZO） transparent conductive layers（TCLs） has been demonstrated.The AZO-TCLs were fabricated on the n-＋-InGaN contact layer by metal organic chemical vapor deposition（MOCVD） using H2O as an oxidizer at temperatures as low as 400 ℃ without any post-deposition annealing.It shows a high transparency（98%）,low resistivity（510 -4 Ω·cm）,and an epitaxial-like excellent interface on p-GaN with an n＋-InGaN contact layer.A forward voltage of 2.82 V @ 20 mA was obtained.Most importantly,the power efficiencies can be markedly improved by 53.8%@20 mA current injection and 39.6%@350 mA current injection compared with conventional LEDs with indium tin oxide TCL（LED-Ⅲ）,and by28.8%@20 mA current injection and 4.92%@350 mA current injection compared with LEDs with AZO-TCL prepared by MOCVD using O2 as an oxidizer（LED-Ⅱ）,respectively.The results indicate that the AZO-TCL grown by MOCVD using H2O as an oxidizer is a promising TCL for a low-cost and high-efficiency GaN-based LED application.
基金supported by the National Key Basic Research Program of China(No.2012CB619200)the National Natural Science Foundation of China(No.61474053)+1 种基金the State Key Laboratory for Mechanical Behavior of Materials of Xi'an Jiaotong University(No.20161806)the Natural Science Basic Research Open Foundation of the Key Lab of Automobile Materials,Ministry of Education,Jilin University(No.1018320144001)
文摘Microstructure and misfit dislocation behavior in In_xGa_(1-x)As/InP heteroepitaxial materials grown by low pressure metal organic chemical vapor deposition(LP-MOCVD) were analyzed by high resolution transmission electron microscopy(HRTEM), scanning electron microscopy(SEM), atomic force microscopy(AFM), Raman spectroscopy and Hall effect measurements. To optimize the structure of In_(0.82)Ga_(0.18)As/InP heterostructure, the In_xGa_(1-x)As buffer layer was grown. The residual strain of the In_(0.82)Ga_(0.18)As epitaxial layer was calculated. Further, the periodic growth pattern of the misfit dislocation at the interface was discovered and verified. Then the effects of misfit dislocation on the surface morphology and microstructure of the material were studied. It is found that the misfit dislocation of high indium(In) content In_(0.82)Ga_(0.18)As epitaxial layer has significant influence on the carrier concentration.
基金supported by the National Natural Science Foundation of China(11904108)Guangdong Basic and Applied Basic Research Foundation(2020B1515020032)"The pearl River Talent Recruitment Program"(2019ZT08X639)。
文摘In this work,a novel ultraviolet(UV)photodetector(PD)based on AlGaN/u-GaN/p-GaN/u-GaN heterojunction high electron mobility transistor(HEMT)has been developed.This HEMT epilayer is grown using the metal-organic chemical vapor deposition(MOCVD)technique,and the growth parameters,including the AlGaN growth temperature,preheating temperature of the p-GaN layer,and NH3/N2 flow rate,are optimized to improve the quality of the epilayer.The optimized epilayer exhibits a flat surface with a root mean square value of 0.146 nm and low dislocation density.The p-GaN thickness in epitaxial wafers has a significant influence on electrical and UV photoresponse.With a p-GaN of 1µm,the UV PD demonstrates a significant switching ratio and transconductance of 107 and 127.3 mS mm^(-1),respectively.Acting as a UV PD,it also exhibits a high light on/off ratio(I_(light)/I_(dark))of 6.35×10^(5),a high responsivity(R)of 48.11 A W^(-1),and a detectivity(D*)of 6.85×10^(12)Jones under 365-nm UV illumination with light power density of 86.972 mW cm^(-2).The high-performance HEMT and UV detectors,which incorporate p-GaN etchless technology,have been refined through advancements in epitaxial growth and structural design.These improvements solidify the groundwork for large-scale manufacturing of UV communication systems and laser diodes.
