Optical and Transport Properties of Single Quantum Well Infrared Photodetectors

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Abstract
We have studied the optical and transport properties of AlGaAs/GaAs single quantum well infrared photodetectors (SQWIPs). The SQWIP shows a narrowband photocurrent at around 9.2 µm, due to intersubband transition in the steady state characteristics, measured using a Fourier transform infrared spectrometer. The bias voltage dependence of the magnitude and the spectral shape of the observed steady state photocurrent indicates that the photocurrent is strongly affected by the tunneling escape process. Furthermore, a transient photoresponse of the SQWIP has been studied using free electron laser (FEL) pulses. A comparison of the steady state photocurrent and the transient photoresponse shows that the charging current induced by the band bending effect contributes to an increased photo sensitivity.