Influence of Si-Doping on the Performance of InGaN/GaN Multiple Quantum Well Solar Cells

Resumo

The performance of InGaN/GaN multiple quantum well (MQW) solar cells with five different Si-doping concentrations, namely 0, 4 × 10¹⁷ cm^–3, 1 × 10¹⁸ cm^–3, 3 × 10¹⁸ cm^–3 and 6 × 10¹⁸ cm^–3, in GaN barriers is investigated. Increasing Si-doping concentration leads to better transport property, resulting in smaller series resistance (R_s). However, the crystal quality degrades when Si-doping concentration is over 1 × 10¹⁸ cm^–3, which reduces the external quantum efficiency, short circuit current density and open circuit voltage. As a result, the sample with a slight Si-doping concentration of 4 × 10¹⁷ cm^–3 exhibits the highest conversion efficiency.