Near-infrared sensors for high efficiency and high-temperature operation enabled by ultra-thin type-II quantum wells and photon-trapping structures

Abstract

We present a multi-quantum well (MQW)-based photodetectors design method for a 1-3 μm wavelength selectivity range using the finite difference time domain (FDTD) Lumerical platform. We demonstrate absorption coefficient and power absorption profile modulation in an III-V-based type-II MQW stack embedded with photon-trapping (PT) surface structures. We present an MQW-based photodetectors design space by varying the MQW stacking period, and the well and the barrier dimensions from 100-200 and 5-10 nm respectively. We show that the power absorption in the MQW increases for a fixed wavelength sensitivity range. However, the well and the barrier dimension variation facilitate the wavelength sensitivity range modulation. The upper bound of 3 μm on the wavelength-selectivity is achieved by tuning the well/barrier widths. We further proposed a modified device structure to cap the lower wavelength optical signal and cap them at 1 μm. We also show a tremendous increase in power absorption by introducing photon-trapping holes into the MQW structure. Finally, we extract the effective absorption coefficient of the MQW using the power absorption profile generated in the FDTD framework to show the desired wavelength selectivity. Finally, we utilize the extracted absorption coefficient to perform a COMSOL-based simulation to show a 31% enhancement in quantum efficiency of the MQW detector with the introduction of photon-trapping holes.