Observation of Quantum-Confined Stark Effect in Triple-Coupled InGaAs/ GaAs/AlGaAs Quantum Well Infrared Photodetector.

摘要

We have investigated the quantum-confined Stark effect (QCSE) in several n-type InGaAs/GaAs/AlGaAs triple-coupled quantum well infrared photodetectors (TC-QWIPs) for 8-12 micrometers long wavelength infrared (LWIR) detection. The basic structure of this TC-QWIP consists of three coupled quantum wells (QWs) formed by a Si-doped In(x)Ga(1-x)As QW and two undoped thin GaAs QWs separated by two thin Al(y)Ga(1-y)As barriers. Three TC-QWIP devices with varying indium and aluminum compositions were fabricated and characterized. A strong QCSE for the (E1 to E3) transition was observed in the wavelength range of 8.2 - 9.1 micrometers, 10.8 - 11.5 micrometers, and 9.4 - 10.7 micrometers for QWIP-A, -B, and -C, respectively. These devices exhibit a linear dependence of peak wavelength on the applied bias voltage over these wavelengths ranges. Peak responsivities, R(1) = 0.05, 0.33 A/W and detectivities, D*(BLIP) = 6. 1x10(exp9), l.63x10(exp10)cm-Hz(1/2)/W at V(b)=5, 4 V, lamba(p)=8.6, 11.2 micrometers, and T(BLIP)=66, 50 K were obtained for QWIP-A and -B, respectively. For QWIP-C, R(1)=0.19 A/W was obtained at lamba(p)=9.3 micrometers, V(b)=7 V, and T+60 K.