Quantum wells and superlattices for III-V photovoltaics and photodetectors

Abstract

Semiconductor quantum wells and superlattices have found numerous applications in optoelectronic devices, such as lasers, LEDs and SOAs, and are an increasingly common feature of high efficiency solar cells and photodetectors. In this paper we will highlight some of the recent developments in the use of low-dimensional III-V semiconductors to improve the performance of photovoltaics by tailoring the bandgap of the junction. We also discuss novel structures designed to maximize photo-generated carrier escape and the application of quantum confinement to other components of the solar cell, such as tunnel junctions. Recent developments in type-II superlattices for photodetectors will also be discussed, including the graded-gap LWIR device based on the W-structured superlattices demonstrated at the Naval Research Laboratory. Modeled results will be presented using the NRL BANDS^TM integrated 8-band kp and Poisson solver, which was developed for computing the bandstructures of superlattice and multi-quantum well photodiodes