Theε-Ga2O3 p-n heterojunctions(HJ)have been demonstrated using typical p-type oxide semiconductors(NiO or SnO).Theε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition(MOCVD)with thr...Theε-Ga2O3 p-n heterojunctions(HJ)have been demonstrated using typical p-type oxide semiconductors(NiO or SnO).Theε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition(MOCVD)with three-step growth method.The polycrystalline SnO and NiO thin films were deposited on theε-Ga2O3 thin film by electron-beam evaporation and thermal oxidation,respectively.The valence band offsets(VBO)were determined by x-ray photoelectron spectroscopy(XPS)to be 2.17 eV at SnO/ε-Ga2O3 and 1.7 eV at NiO/ε-Ga2O3.Considering the bandgaps determined by ultraviolet-visible spectroscopy,the conduction band offsets(CBO)of 0.11 eV at SnO/ε-Ga2O3 and 0.44 eV at NiO/ε-Ga2O3 were obtained.The type-Ⅱband diagrams have been drawn for both p-n HJs.The results are useful to understand the electronic structures at theε-Ga2O3 p-n HJ interface,and design optoelectronic devices based onε-Ga2O3 with novel functionality and improved performance.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
基金Project supported by the National Natural Science Foundation of China(Grant No.61774172)the Guangdong Provincial Department of Science and Technology,China(Grant Nos.2019B010132002 and 2016B090918106)+1 种基金the Pengcheng Scholar Funding(2018)Shenzhen Science and Technology Innovation Committee,China(Grant No.KQJSCX20180323174713505).
文摘Theε-Ga2O3 p-n heterojunctions(HJ)have been demonstrated using typical p-type oxide semiconductors(NiO or SnO).Theε-Ga2O3 thin film was heteroepitaxial grown by metal organic chemical vapor deposition(MOCVD)with three-step growth method.The polycrystalline SnO and NiO thin films were deposited on theε-Ga2O3 thin film by electron-beam evaporation and thermal oxidation,respectively.The valence band offsets(VBO)were determined by x-ray photoelectron spectroscopy(XPS)to be 2.17 eV at SnO/ε-Ga2O3 and 1.7 eV at NiO/ε-Ga2O3.Considering the bandgaps determined by ultraviolet-visible spectroscopy,the conduction band offsets(CBO)of 0.11 eV at SnO/ε-Ga2O3 and 0.44 eV at NiO/ε-Ga2O3 were obtained.The type-Ⅱband diagrams have been drawn for both p-n HJs.The results are useful to understand the electronic structures at theε-Ga2O3 p-n HJ interface,and design optoelectronic devices based onε-Ga2O3 with novel functionality and improved performance.
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.
