Investigation of an InGaN Based Quantum Well Solar Cell Using Silvaco TCAD

Abstract

This work aims to investigate a Quantum Well Solar Cell (QWSC) that employs the same alloy material for all the layers of the solar cell structure. Silvaco TCAD software tool is used to implement the desired QWSC, where the same III-V group-based Indium Gallium Nitride (InGaN) alloy has been proposed as the material for its different layers, because of its ability to have a widely varying band-gap due to varying compositions. The same alloy with different combinations provides a band gap appropriate for each layer while reducing lattice-mismatch between the layers to the minimum, thereby helping achieve high conversion efficiency. The same InGaN material is used as the Quantum Wells (QWs) embedded in the intrinsic InGaN-based absorber layer. This absorber layer is sandwiched between the heavily doped base and emitter regions to provide a uniform field to help escape all the photogenerated carriers from the QWs. Extensive simulation runs have been conducted in the Silvaco TCAD environment to investigate the effects of number, width and depth of these QWs on the various performance metrics of the proposed QWSC, which include short circuit current density, open circuit voltage, fill factor and conversion efficiency. The role of the Back-Surface Field (BSF) layer on these performance metrics has also been investigated. The performance metrics of the proposed QWSC are also compared with those of a GaAs/InAs-based QWSC implemented in Silvaco with a similar structure and state-of-the-art QWSCs mentioned in the literature. These investigations reveal that the proposed QWSC is promising for realizing a high-efficiency solar cell.