Dependence of the vertical-tunnel-junction GaAs solar cell on concentration and temperature

Abstract

Modelling the current–voltage (I–V) characteristics of photovoltaic (PV) devices is important for understanding their behaviour and potential. Typically, the single exponential model (SEM) is used because of its simplicity and accuracy. In this work, we validate the SEM for a gallium arsenide (GaAs) vertical-tunnel-junction (VTJ) using TCAD software. This cell is the key to overcoming the series resistance limitations of current concentrator solar cells, which can lead to the development of ultra-high concentrator photovoltaic systems (UHCPV) with concentrations (Cratio) greater than 1000 suns. The results indicate that the SEM is a suitable tool to model the I–V characteristics of the VTJ cell with mean errors lower than 1%. Moreover, the solar cell did not show any limitations regarding the Cratio and temperatures under investigation. In addition, the analysis of the temperature coefficients of the cell demonstrates that their dependency on temperature reduces as Cratio increases. The results of this work suggest that VTJ is a promising solution to produce a new generation of high-efficiency and low-cost UHCPV systems.