GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nan...GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nanowires(NWs)is hindered by type-Ⅱquantum well structures arising from the mixture of zinc blende(ZB)and wurtzite(WZ)phases and surface defects due to the large surface-to-volume ratio.Achieving GaAs-based NWs with high emission efficiency has become a key research focus.In this study,pre-etched silicon substrates were combined with GaAs/AlGaAs core-shell heterostructure to achieve GaAs-based NWs with good perpendicularity,excellent crystal structures,and high emission efficiency by leveraging the shadowing effect and surface passivation.The primary evidence for this includes the prominent free-exciton emission in the variable-temperature spectra and the low thermal activation energy indicated by the variable-power spectra.The findings of this study suggest that the growth method described herein can be employed to enhance the crystal structure and optical properties of otherⅢ-Ⅴlow-dimensional materials,potentially paving the way for future NW devices.展开更多
量子阱红外探测器(Quantum well infrared photodetector,QWIP)已经经历了20多年的深入研究,各种QWIP器件,包括量子阱红外探测器焦平面阵列(FPA)的研制也已经相当成熟。但是在国内,受制于整体工业水平,QWIP焦平面阵列器件的研制仍然处...量子阱红外探测器(Quantum well infrared photodetector,QWIP)已经经历了20多年的深入研究,各种QWIP器件,包括量子阱红外探测器焦平面阵列(FPA)的研制也已经相当成熟。但是在国内,受制于整体工业水平,QWIP焦平面阵列器件的研制仍然处于起步阶段。研制了基于GaAs/AlxGa1-xAs材料、峰值响应波长为9.9μm的长波320×256 n型QWIP焦平面阵列器件,其像元中心距25μm,光敏元面积为22μm×22μm。GaAs衬底减薄后的QWIP焦平面阵列,与Si基CMOS读出电路(ROIC)通过铟柱倒焊互连,并且在65 K工作温度下进行了室温环境目标成像。该焦平面器件的规模和成像质量相比之前国内报道的结果都有较大提高。焦平面平均峰值探测率达1.5×1010cm.Hz1/2/W。展开更多
在分子束外延生长量子阱材料过程中 ,分析了在不同的 Ga As/ Al Ga As异质结生长次序中 Ga的解吸附速率不同和量子阱中掺杂的扩散造成量子阱结构的不对称 ,讨论了 Ga As/ Al Ga As量子阱红外探测器的性能参数相对于正负偏压的不对称性 ...在分子束外延生长量子阱材料过程中 ,分析了在不同的 Ga As/ Al Ga As异质结生长次序中 Ga的解吸附速率不同和量子阱中掺杂的扩散造成量子阱结构的不对称 ,讨论了 Ga As/ Al Ga As量子阱红外探测器的性能参数相对于正负偏压的不对称性 ,并与金属有机化合物汽相沉淀法生长的量子阱材料和相应器件进行了比较 .发现 。展开更多
用投掷法和有限元差分法计算了单周期调制掺杂GaAs/AlGaAs双量子阱的能带结构,得到基态能级与第一激发态的能级差为43.3 meV,并由此推算得到产生载流子横向转移效应的电场强度为1.2～1.8 k V/cm之间.采用MBE技术生长了所涉及的双量子阱...用投掷法和有限元差分法计算了单周期调制掺杂GaAs/AlGaAs双量子阱的能带结构,得到基态能级与第一激发态的能级差为43.3 meV,并由此推算得到产生载流子横向转移效应的电场强度为1.2～1.8 k V/cm之间.采用MBE技术生长了所涉及的双量子阱结构,通过优化退火条件,获得了较理想的金属—半导体接触条件.在此基础上,测得在电场强度为1.5 k V/cm时,电流—电压曲线呈现出负阻特性.该电场强度区别于GaAs耿氏效应的电场强度,由此判定,产生微分负阻的机理是电子由高迁移率导电层到低迁移率导电层的横向转移所致,即实空间转移.展开更多
A complete quantum mechanical model for GaAs?AlGaAs quantum well infrared photodetectors(QWIPs) is presented here. The model consisted of four parts: (1) Starting with the description of the electromagnetic field of t...A complete quantum mechanical model for GaAs?AlGaAs quantum well infrared photodetectors(QWIPs) is presented here. The model consisted of four parts: (1) Starting with the description of the electromagnetic field of the infrared radiation in the QWIP, effective component of the vector potential <| A z |> along the QWIP growth direction ( z axis) due to the optical diffraction grating was calculated. (2) From the wave transmissions and the occupations of the electronic states, it was discussed that the dark current in the QWIP is determined by the drift diffusion current of carriers thermally excited from the ground sublevel in the quantum well to extended states above the barrier. (3) The photocurrent was investigated by the optical transition (absorption coefficient between the ground state to excited states due to the nonzero <| A z |> ). (4) By studying the inter diffusion of the Al atoms across the GaAs?AlGaAs heterointerfaces,the mobility of the drift diffusion carriers in the excited states was calculated, so the measurement results of the dark current and photocurrent spectra can be explained theoretically. With the complete quantum mechanical descriptions of (1 4), QWIP device design and optimization are possible.展开更多
用分子束外延系统生长了 Ga As/ Al Ga As非对称耦合双量子阱 (ACDQW) ,用组合注入的方法 ,在同一块衬底上获得了不同注入离子和不同注入剂量的耦合量子阱单元 ,没有经过快速热退火过程 ,在常温下测量了不同单元的显微光荧光谱 ,发现子...用分子束外延系统生长了 Ga As/ Al Ga As非对称耦合双量子阱 (ACDQW) ,用组合注入的方法 ,在同一块衬底上获得了不同注入离子和不同注入剂量的耦合量子阱单元 ,没有经过快速热退火过程 ,在常温下测量了不同单元的显微光荧光谱 ,发现子带间跃迁能量最大变化范围接近 10 0 me V。展开更多
文摘GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nanowires(NWs)is hindered by type-Ⅱquantum well structures arising from the mixture of zinc blende(ZB)and wurtzite(WZ)phases and surface defects due to the large surface-to-volume ratio.Achieving GaAs-based NWs with high emission efficiency has become a key research focus.In this study,pre-etched silicon substrates were combined with GaAs/AlGaAs core-shell heterostructure to achieve GaAs-based NWs with good perpendicularity,excellent crystal structures,and high emission efficiency by leveraging the shadowing effect and surface passivation.The primary evidence for this includes the prominent free-exciton emission in the variable-temperature spectra and the low thermal activation energy indicated by the variable-power spectra.The findings of this study suggest that the growth method described herein can be employed to enhance the crystal structure and optical properties of otherⅢ-Ⅴlow-dimensional materials,potentially paving the way for future NW devices.
文摘在分子束外延生长量子阱材料过程中 ,分析了在不同的 Ga As/ Al Ga As异质结生长次序中 Ga的解吸附速率不同和量子阱中掺杂的扩散造成量子阱结构的不对称 ,讨论了 Ga As/ Al Ga As量子阱红外探测器的性能参数相对于正负偏压的不对称性 ,并与金属有机化合物汽相沉淀法生长的量子阱材料和相应器件进行了比较 .发现 。
文摘用投掷法和有限元差分法计算了单周期调制掺杂GaAs/AlGaAs双量子阱的能带结构,得到基态能级与第一激发态的能级差为43.3 meV,并由此推算得到产生载流子横向转移效应的电场强度为1.2～1.8 k V/cm之间.采用MBE技术生长了所涉及的双量子阱结构,通过优化退火条件,获得了较理想的金属—半导体接触条件.在此基础上,测得在电场强度为1.5 k V/cm时,电流—电压曲线呈现出负阻特性.该电场强度区别于GaAs耿氏效应的电场强度,由此判定,产生微分负阻的机理是电子由高迁移率导电层到低迁移率导电层的横向转移所致,即实空间转移.
文摘A complete quantum mechanical model for GaAs?AlGaAs quantum well infrared photodetectors(QWIPs) is presented here. The model consisted of four parts: (1) Starting with the description of the electromagnetic field of the infrared radiation in the QWIP, effective component of the vector potential <| A z |> along the QWIP growth direction ( z axis) due to the optical diffraction grating was calculated. (2) From the wave transmissions and the occupations of the electronic states, it was discussed that the dark current in the QWIP is determined by the drift diffusion current of carriers thermally excited from the ground sublevel in the quantum well to extended states above the barrier. (3) The photocurrent was investigated by the optical transition (absorption coefficient between the ground state to excited states due to the nonzero <| A z |> ). (4) By studying the inter diffusion of the Al atoms across the GaAs?AlGaAs heterointerfaces,the mobility of the drift diffusion carriers in the excited states was calculated, so the measurement results of the dark current and photocurrent spectra can be explained theoretically. With the complete quantum mechanical descriptions of (1 4), QWIP device design and optimization are possible.
文摘用分子束外延系统生长了 Ga As/ Al Ga As非对称耦合双量子阱 (ACDQW) ,用组合注入的方法 ,在同一块衬底上获得了不同注入离子和不同注入剂量的耦合量子阱单元 ,没有经过快速热退火过程 ,在常温下测量了不同单元的显微光荧光谱 ,发现子带间跃迁能量最大变化范围接近 10 0 me V。
