AlGaAs/GaAs Triple Quantum Well Photodetector at $5~\mu \text{m}$ Wavelength—A Simulation Study

Abstract

A novel AlGaAs/GaAs triple quantum well (QW) photodetector at 5- $\mu \text{m}$ wavelength has been proposed. The photodetector is designed with a double-resonance condition to achieve short tunneling time and large electron escape probability. The interface optical phonon modes and the phonon-assisted electron transition rates have been calculated. The electron escape probability is as high as 0.8 in the proposed photodetector, which is over two times higher than traditional phonon-assisted tunneling devices. Compared with QW infrared photodetectors, the noise current of the photodetector can be reduced dramatically ( $> 10^{13}$ times at 77 K and >4000 times at 300 K). In addition, the effects of delta doping on the absorption coefficients and scattering times of the triple QW photodetector are also investigated in detail. Delta doping at the middle of the well is much more desirable than uniform doping, in order to achieve large escape probability and high absorption coefficient.