Performance enhancement of a proposed solar cell microstructure based on heavily doped silicon wafers

Abstract

This paper aims to present a proposed npn solar cell microstructure based on low cost heavily doped Silicon wafers. The physical perception of the proposed structure is based on the idea of vertical generation and lateral collection of light generated carriers. It should be mentioned that our structure can be utilized whenever the diffusion length of photogenerated electron hole pairs is smaller than the penetration depth of the solar radiation. The enhancement in the structure performance is attained by the optimization of the structure technological and geometrical parameters and based on practical considerations. This enhancement enables achieving the maximum possible structure conversion efficiency. Moreover, the optical performance, in terms of the spectral response and external quantum efficiency, is presented. The optimization is carried out using SILVACO TCAD process and device simulators. The main parameters used in optimization include the thickness and doping of the top n + layer as well as the sidewall emitter. Additionally, the structure base width along with the notch depth are considered. Finally, back surface treatment is introduced. The structure conversion efficiency in the initial step before optimization was 10.7%. As a result of the optimization process, the structure conversion efficiency is improved to about 15% above the initial case study by 4%.