The epitaxial growth of novel GaN-based light-emitting diode(LED) on Si(100) substrate has proved challenging.Here in this work, we investigate a monolithic phosphor-free semi-polar InGaN/GaN near white light-emitting...The epitaxial growth of novel GaN-based light-emitting diode(LED) on Si(100) substrate has proved challenging.Here in this work, we investigate a monolithic phosphor-free semi-polar InGaN/GaN near white light-emitting diode, which is formed on a micro-striped Si(100) substrate by metal organic chemical vapor deposition. By controlling the size of micro-stripe, InGaN/GaN multiple quantum wells(MQWs) with different well widths are grown on semi-polar(1■01)planes. Besides, indium-rich quantum dots are observed in InGaN wells by transmission electron microscopy, which is caused by indium phase separation. Due to the different widths of MQWs and indium phase separation, the indium content changes from the center to the side of the micro-stripe. Various indium content provides the wideband emission. This unique property allows the semipolar InGaN/GaN MQWs to emit wideband light, leading to the near white light emission.展开更多
Metalorganic chemical vapor deposition of a crack-free mirror-like surface of InGaN/GaN MQWs on Si(111)substrate is demonstrated,and an InGaN/GaN MQWs solar cell device is fabricated.Photo response measurement of the ...Metalorganic chemical vapor deposition of a crack-free mirror-like surface of InGaN/GaN MQWs on Si(111)substrate is demonstrated,and an InGaN/GaN MQWs solar cell device is fabricated.Photo response measurement of the solar cell devices shows that the fill factor FF=49.4%,open circuit voltage V_(oc)=0.32 V,and short circuit current J_(sc)=0.07 mA/cm^(2),under AM 1.5 G illumination.In order to analyze the influence of material quality on the performance of solar cells,XRD,SEM and Raman scattering experiments are carried out.It is found that insertion of a proper top AlN layer can effectively improve the material quality,and therefore enhance the photovoltaic performance of the fabricated device.展开更多
The influences of stress on the properties of InGaN/GaN multiple quantum wells （MQWs） grown on silicon substrate were investigated. The different stresses were induced by growing InGaN and A1GaN insertion layers （I...The influences of stress on the properties of InGaN/GaN multiple quantum wells （MQWs） grown on silicon substrate were investigated. The different stresses were induced by growing InGaN and A1GaN insertion layers （IL） respectively before the growth of MQWs in metal-organic chemical vapor deposition （MOCVD） system. High resolution x-ray diffrac- tion （HRXRD） and photoluminescence （PL） measurements demonstrated that the InGaN IL introduced an additional ten- sile stress in n-GaN, which released the strain in MQWs. It is helpful to increase the indium incorporation in MQWs. In comparison with MQWs without the IL, the wavelength shows a red-shift. A1GaN IL introduced a compressive stress to compensate the tensile stress, which reduces the indium composition in MQWs. PL measurement shows a blue-shift of wavelength. The two kinds of ILs were adopted to InGaN/GaN MQWs LED structures. The same wavelength shifts were also observed in the electroluminescence （EL） measurements of the LEDs. Improved indium homogeneity with InGaN IL, and phase separation with A1GaN IL were observed in the light images of the LEDs.展开更多
The in-plane optical anisotropy(IPOA) of c-plane In Ga N/Ga N quantum disks(Qdisks) in nanowires grown on MoS_(2)/Mo and Ti/Mo substrates is investigated using reflectance difference spectroscopy(RDS) at room temperat...The in-plane optical anisotropy(IPOA) of c-plane In Ga N/Ga N quantum disks(Qdisks) in nanowires grown on MoS_(2)/Mo and Ti/Mo substrates is investigated using reflectance difference spectroscopy(RDS) at room temperature. A large IPOA related to defect or impurity states is observed. The IPOA of samples grown on MoS_(2)/Mo is approximately one order of magnitude larger than that of samples grown on Ti/Mo substrates. Numerical calculations based on the envelope function approximation have been performed to analyze the origin of the IPOA. It is found that the IPOA primarily results from the segregation of indium atoms in the In Ga N/Ga N Qdisks. This work highlights the significant influence of substrate materials on the IPOA of semiconductor heterostructures.展开更多
We investigate the photoluminescence(PL)emission from InGaN/GaN multiple quantum-well structures before and after 1 MeV electron irradiation.The PL peak intensity exhibits a slight enhancement after low-dose electron ...We investigate the photoluminescence(PL)emission from InGaN/GaN multiple quantum-well structures before and after 1 MeV electron irradiation.The PL peak intensity exhibits a slight enhancement after low-dose electron irradiation(2×10^(13) e/cm^(2)),and then decreases with the cumulative electron dose.Meanwhile,the full width at half maximum of the PL spectrum narrows after low-dose electron irradiation and widens when the irradiation dose is relatively high.With respect to the yellow photoluminescence,there is no significant change until the electron fluence has accumulated up to 10^(14) e/cm^(2).展开更多
Ag纳米粒子的形貌对InGaN/Ga N多量子阱(MQWs)的光致发光(PL)效率有着显著影响。本文采用离子束沉积(IBD)技术将Ag沉积在InGaN/Ga N MQWs上,然后通过快速热退火处理制备Ag纳米粒子。通过改变Ag的沉积时间获得了具有不同Ag纳米粒子形貌...Ag纳米粒子的形貌对InGaN/Ga N多量子阱(MQWs)的光致发光(PL)效率有着显著影响。本文采用离子束沉积(IBD)技术将Ag沉积在InGaN/Ga N MQWs上,然后通过快速热退火处理制备Ag纳米粒子。通过改变Ag的沉积时间获得了具有不同Ag纳米粒子形貌的样品。用原子力显微镜对各样品的Ag纳米粒子形貌和尺寸进行了表征,并且测试了吸收谱、室温和变温PL谱及时间分辨光致发光(TRPL)谱。结果表明:随着Ag沉积时间的延长,所得Ag纳米粒子粒径增大,粒子纵横比先增大后减小且吸收谱峰红移。由于不同形貌的Ag纳米粒子在入射光作用下产生的局域表面等离激元(LSPs)与MQWs中激子耦合强度不同,光发射能力也不同,与没有Ag纳米粒子的样品相比,沉积时间为15 s的样品室温PL积分强度被抑制6.74倍,沉积时间为25 s和35 s的样品室温PL积分强度分别增强1.55和1.72倍且峰位发生红移,沉积时间为45 s的样品室温PL积分强度基本没有变化。TRPL与变温PL的测试结果证明,室温PL积分强度的改变是由于LSPs与MQWs中的激子耦合作用引起的。纵横比大且吸收谱与MQWs的PL谱交叠大的Ag纳米粒子能够更好地增强InGaN/Ga N MQWs的发光。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51472229,61422405,and 11574301)the Natural Science Foundation of Tianjin(Grant No.14JCQNJC01000)the National Science Foundation for Post-doctoral Scientists of China(Grant No.2016M600231)
文摘The epitaxial growth of novel GaN-based light-emitting diode(LED) on Si(100) substrate has proved challenging.Here in this work, we investigate a monolithic phosphor-free semi-polar InGaN/GaN near white light-emitting diode, which is formed on a micro-striped Si(100) substrate by metal organic chemical vapor deposition. By controlling the size of micro-stripe, InGaN/GaN multiple quantum wells(MQWs) with different well widths are grown on semi-polar(1■01)planes. Besides, indium-rich quantum dots are observed in InGaN wells by transmission electron microscopy, which is caused by indium phase separation. Due to the different widths of MQWs and indium phase separation, the indium content changes from the center to the side of the micro-stripe. Various indium content provides the wideband emission. This unique property allows the semipolar InGaN/GaN MQWs to emit wideband light, leading to the near white light emission.
基金Supported by the National Natural Sciences Foundation of China under Grant Nos 61076052 and 60906006the State Key Development Program for Basic Research of China under Grant No 2012CB619303the National High Technology Research and Development Program under Grant No 2011AA050514.
文摘Metalorganic chemical vapor deposition of a crack-free mirror-like surface of InGaN/GaN MQWs on Si(111)substrate is demonstrated,and an InGaN/GaN MQWs solar cell device is fabricated.Photo response measurement of the solar cell devices shows that the fill factor FF=49.4%,open circuit voltage V_(oc)=0.32 V,and short circuit current J_(sc)=0.07 mA/cm^(2),under AM 1.5 G illumination.In order to analyze the influence of material quality on the performance of solar cells,XRD,SEM and Raman scattering experiments are carried out.It is found that insertion of a proper top AlN layer can effectively improve the material quality,and therefore enhance the photovoltaic performance of the fabricated device.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61274039 and 51177175)the National Basic Research Program of China(Grant Nos.2010CB923201 and 2011CB301903)+4 种基金the Ph.D.Program Foundation of the Ministry of Education of China(Grant No.20110171110021)the International Science and Technology Collaboration Program of China(Grant No.2012DFG52260)the National High Technology Research and Development Program of China(Grant No.2014AA032606)the International Science and Technology Collaboration Program of Guangdong Province,China(Grant No.2013B051000041)the Opened Fund of the State Key Laboratory on Integrated Optoelectronics(Grant No.IOSKL2014KF17)
文摘The influences of stress on the properties of InGaN/GaN multiple quantum wells （MQWs） grown on silicon substrate were investigated. The different stresses were induced by growing InGaN and A1GaN insertion layers （IL） respectively before the growth of MQWs in metal-organic chemical vapor deposition （MOCVD） system. High resolution x-ray diffrac- tion （HRXRD） and photoluminescence （PL） measurements demonstrated that the InGaN IL introduced an additional ten- sile stress in n-GaN, which released the strain in MQWs. It is helpful to increase the indium incorporation in MQWs. In comparison with MQWs without the IL, the wavelength shows a red-shift. A1GaN IL introduced a compressive stress to compensate the tensile stress, which reduces the indium composition in MQWs. PL measurement shows a blue-shift of wavelength. The two kinds of ILs were adopted to InGaN/GaN MQWs LED structures. The same wavelength shifts were also observed in the electroluminescence （EL） measurements of the LEDs. Improved indium homogeneity with InGaN IL, and phase separation with A1GaN IL were observed in the light images of the LEDs.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 62074036, 61674038, and 11574302)Foreign Cooperation Project of Fujian Province (Grant No. 2023I0005)+2 种基金Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics (Grant No. KF202108)the National Key Research and Development Program (Grant No. 2016YFB0402303)the Foundation of Fujian Provincial Department of Industry and Information Technology of China (Grant No. 82318075)。
文摘The in-plane optical anisotropy(IPOA) of c-plane In Ga N/Ga N quantum disks(Qdisks) in nanowires grown on MoS_(2)/Mo and Ti/Mo substrates is investigated using reflectance difference spectroscopy(RDS) at room temperature. A large IPOA related to defect or impurity states is observed. The IPOA of samples grown on MoS_(2)/Mo is approximately one order of magnitude larger than that of samples grown on Ti/Mo substrates. Numerical calculations based on the envelope function approximation have been performed to analyze the origin of the IPOA. It is found that the IPOA primarily results from the segregation of indium atoms in the In Ga N/Ga N Qdisks. This work highlights the significant influence of substrate materials on the IPOA of semiconductor heterostructures.
基金Supported by the National Natural Science Foundation of China under Grant No 11275262.
文摘We investigate the photoluminescence(PL)emission from InGaN/GaN multiple quantum-well structures before and after 1 MeV electron irradiation.The PL peak intensity exhibits a slight enhancement after low-dose electron irradiation(2×10^(13) e/cm^(2)),and then decreases with the cumulative electron dose.Meanwhile,the full width at half maximum of the PL spectrum narrows after low-dose electron irradiation and widens when the irradiation dose is relatively high.With respect to the yellow photoluminescence,there is no significant change until the electron fluence has accumulated up to 10^(14) e/cm^(2).
文摘Ag纳米粒子的形貌对InGaN/Ga N多量子阱(MQWs)的光致发光(PL)效率有着显著影响。本文采用离子束沉积(IBD)技术将Ag沉积在InGaN/Ga N MQWs上,然后通过快速热退火处理制备Ag纳米粒子。通过改变Ag的沉积时间获得了具有不同Ag纳米粒子形貌的样品。用原子力显微镜对各样品的Ag纳米粒子形貌和尺寸进行了表征,并且测试了吸收谱、室温和变温PL谱及时间分辨光致发光(TRPL)谱。结果表明:随着Ag沉积时间的延长,所得Ag纳米粒子粒径增大,粒子纵横比先增大后减小且吸收谱峰红移。由于不同形貌的Ag纳米粒子在入射光作用下产生的局域表面等离激元(LSPs)与MQWs中激子耦合强度不同,光发射能力也不同,与没有Ag纳米粒子的样品相比,沉积时间为15 s的样品室温PL积分强度被抑制6.74倍,沉积时间为25 s和35 s的样品室温PL积分强度分别增强1.55和1.72倍且峰位发生红移,沉积时间为45 s的样品室温PL积分强度基本没有变化。TRPL与变温PL的测试结果证明,室温PL积分强度的改变是由于LSPs与MQWs中的激子耦合作用引起的。纵横比大且吸收谱与MQWs的PL谱交叠大的Ag纳米粒子能够更好地增强InGaN/Ga N MQWs的发光。
