Current oscillations and stable electric field domains in doped GaAs/AlAs superlattices

The crossover between two regimes has been observed in the vertical electric transport of weakly coupled GaAs/AlAs superlattices (SLs). At fixed d.c. bias, the SLs can be triggered by illumination to switch from a regime of temporal current oscillation to the formation of a stable electric field domain. The conversion can be reversed by raising the sample temperature to about 200 K. An effective carrier injection model is proposed to explain the conversion processes, taking into account the contact resistance originating from DX centres in the n(+)-Al0.5Ga0.5As contact layers which is sensitive to light illumination and temperature. In addition, quasiperiodic oscillations have been observed at a particular d.c. bias voltage.

Evidence of Gamma-X sequential resonant tunneling in GaAs/AlAs superlattices

We have studied the sequential resonant tunneling of doped weakly coupled GaAs/AlAs superlattices under hydrostatic pressure up to 4.5 kbar. The pressure coefficient obtained from the experiment, 15.3 meV/kbar, provides a strong evidence for the formation of the electric field domain due to Gamma-X sequential resonant tunneling, At the same time, we have observed the transition between two kinds of sequential resonant tunneling processes within the pressure range from 0 to 4.5 kbar, where the transition pressure between Gamma-Gamma and Gamma-X sequential resonant tunneling is P-t similar to 1.6 kbar. For P < P-t, the electric field domain is formed by Gamma-Gamma sequential resonant tunneling, while for P > P-t, the electric field domain is preferably formed by Gamma-X sequential resonant tunneling. (C) 1996 American Institute of Physics.

An investigation of the formation mechanisms of electric field domains in GaAs/AlAs superlattices

We have studied the vertical transport and formation mechanisms of electric field domains in doped weakly-coupled GaAs/AlAs superlattices. Under hydrostatic pressure two kinds of sequential resonant tunneling are observed within the pressure range from 0 to 4.5 kbar. A transition from Gamma-Gamma to Gamma-X sequential resonant tunneling occurs at P-t approximate to 1.6 kbar. For P < P-t, the high electric field domain is formed by the Gamma-Gamma process, while for P > P-t it is preferentially formed by the Gamma-X process.

A voltage-controlled tunable two-color infrared photodetector using GaAs/AlAs/GaAlAs and GaAs/GaAlAs stacked multiquantum wells

A voltage-controlled tunable two-color infrared detector with photovoltaic (PV) and photoconductive (PC) dual-mode operation at 3-5 mu m and 8-14 mu m using GaAs/AlAs/AlGaAs double barrier quantum wells (DBQWs) and bound-to-continuum GaAs/AlGaAs quantum wells is demonstrated. The photoresponse peak of the photovoltaic GaAs/AlAs/GaAlAs DBQWs is at 5.3 mu m, and that of the photoconductive GaAs/GaAlAs quantum wells is at 9.0 mu m. When the two-color detector is under a zero bias, the spectral response at 5.3 mu m is close to saturate and the peak detectivity at 80 K can reach 1.0X10(11) cmHz(1/2)/W, while the spectral photoresponsivity at 9.0 mu m is absolutely zero completely. When the external voltage of the two-color detector is changed to 2.0 V, the spectral photoresponsivity at 5.3 mu m becomes zero while the spectral photoresponsivity at 9.0 mu m increases comparable to that at 5.3 mu m under zero bias, and the peak detectivity (9.0 mu m) at 80 K can reach 1.5X10(10) cmHz(1/2)/W. Strictly speaking, this is a real bias-controlled tunable two-color infrared photodetector. We have proposed a model based on the PV and PC dual-mode operation of stacked two-color QWIPs and the effects of tunneling resonance with narrow energy width of photoexcited electrons in DBQWs, which can explain qualitatively the voltage-controlled tunable behavior of the photoresponse of the two-color infrared photodetector. (C) 1996 American Institute of Physics.

GaAs/GaAlAs量子阱激子能量调谐的新方法

用分子束外延技术(MBE)在GaAs量子阱中嵌入InAs亚单层，可以有效地改变量子阱的激子能量，从而达到波长调谐的目的。激子能量的调谐范围取决于量子阱宽度，并和InAs层厚度有关。利用有效质量近似，计算给出了能量调谐曲线，结果与实验符合较好。该文给出的结果提供了一种改变量子阱发光器件波长的新方法。

GaAs/GaAlAs量子阱双色红外探测器的光电性质的研究

综述了有关新型的GaAs/AlGaAs体系双色量子阱红外探测器的结构特性和光电特性的研究工作，双色探测器工作在3～5μm及8～12μm大气窗口波段范围，是光伏响应模式和光导响应模式相结合的偏压控制型两端器件，研究内容包括探测器的器件结构特性、红外光吸收特性、红外光电流响应、暗电流、噪声特性和探测率测试分析等等。首次从理论和实验两方面探讨有关量子阱束缚子能带到扩展态中不同虚能级之间的光跃迁问题及光电子输运问题。

GaAs/GaAlAs中红外量子阱探测器和双色量子阱红外探测器

报道GaAs/GaAlAs中红外(3～5μm)量子阱探测器和双色量子阱红外探测器的制备和性能。GaAs/GaAlAs中红外量子阱探测器是光伏型,探测峰值波长为5.3μm,85K下的500K黑体探测率为3.0×10~9cm·Hz~(1/2)/W,峰值探测率达到5×10~(11)cm·Hz~(1/2)/W,阻抗为50MΩ。GaAs/GaAlAs双色量子阱红外探测器是偏压控制型的两端器件,在零偏压下该探测器仅在3～5μm波段有响应,响应峰值波长为5.3μm,85K温度下550K黑体探测率为3.0×10~9cm·Hz~(1/2)/W,当偏压为2V时,该探测器的响应切换到8～12μm波段,峰值响应波长为9.0μm,85K温度下的黑体探测率为1.0×10~9cm·Hz~(1/2)/W。

GaAs/GaAlAs多量子阱反射型光调制器及自电光效应器件

采用分子束外延技术生长含有大周期数的GaAs/GaAlAs多量子阱(MQW)及分布布喇格反射器(DBR)的PIN结构器件。研究了量子限制斯塔克效应(QCSE),分布布喇格反射及非对称腔模(ASFP)效应对光的反射调制作用及这三种效应的兼容性对光调制及逻辑器件的重要影响,给出研制的反射型光调制器及自电光效应器件的实验结果,对于常通型及常闭型调制器,其两态衬比度可达10 dB。所研制的SEED器件,其导通光能耗低于10 fJ/(μm)~2,实现其光学双稳态及R-S光触发器工作。

GaAs/GaAlAs多量子阱（CCTS）结构双稳态激光器的实验研究

报道了GaAs/GaAlAs多量子阱(MQW)双区共腔(CCTS)结构的双稳态激光器.该器件利用多次离子注入形成电隔离很好的双电极结构,吸收区上加上一定反偏电压时得到了双稳特性,观察到了器件工作于双稳态时对光谱边模的显著抑制.

GaAs/GaAlAs单量子阱光调制器电学行为

利用导纳谱研究了GaAs/GaAlAs单量子阱光调制器的电学行为, 观察到了量子阱中电子或空穴子能带的“场致去局域化”的物理现象。

透射窗口型GaAs/GaAlAs掩埋异质结构激光器

于2010-11-23批量导入