Enhanced p-type dopability of P and As in CdTe using non-equilibrium thermal processing

• DOI: 10.1063/1.4926748
• Publication Date: 2015-07-14T18:37:51Z
• Authors: Ji-Hui Yang; Wan-Jian Yin; Ji-Sang Park; James Burst; Wyatt K. Metzger; Tim Gessert; Teresa Barnes; Su-Huai Wei
• Keywords: Cadmium telluride photovoltaics; Limiting; Open-circuit voltage

One of the main limiting factors in CdTe solar cells is its low p-type dopability and, consequently, open-circuit voltage (VOC). We have systematically studied P and As doping with first-principles calculations order to understand how increase hole density. find that both are self-compensated by formation AX centers. More importantly, we although high-temperature growth beneficial obtain high density, rapid cooling necessary sustain density lower Fermi level close valence band maximum (VBM) at room temperature. Thermodynamic simulations suggest from a temperature under Te-poor conditions choosing an optimal dopant concentration about 1018/cm3, can reach above 1017/cm3 within ∼0.1 eV VBM. These results promising pathway improve VOC efficiency cells.