Near-infrared high-gain strained layer InGaAs heterojunction phototransistors: Resonant periodic absorption

Abstract

We report high-gain phototransistors on GaAs substrates at wavelengths for which GaAs substrates are transparent, and hence, are promising for optoelectronic interconnect, optical-logic device, neural network, and lightwave communication applications. Using a new technique called resonant periodic absorption we have achieved high-optical gain at previously inaccessible wavelengths (≳925 nm). Resonant periodic absorption is achieved in an asymmetric microresonator consisting of a strained-layer InGaAs/GaAs heterojunction phototransistor sandwiched between distributed Bragg reflectors. By aligning the optical intensity maxima with the InGaAs quantum wells in the collector region of the phototransistor, we dramatically enhance the optical absorption.