Wavelength Tuning of GaAs/AlGaAs Quantum-Well Infrared Photodetectors by Thermal Interdiffusion

Abstract

Thermal interdiffusion is used to shift peak response wavelength of quantum well infrared photodetectors. A maximum 0.7 µm red-shift for 900°C annealed devices compared with as-grown one has been obtained. Error function potential profile is used to calculate the intermixing process. The large red-shift is attributed to Si-dopant enhanced intermixing. Dark current is decreased about 5 times for 900°C annealed sample than as-grown one, which is attributed to Si-dopant out-diffusion. The experimentally observed reduction in the responsivity is attributed to out-diffusion of Si-dopant and degradation of interfaces.