High‐rate deposition of epitaxial layers for efficient low‐temperature thin film epitaxial silicon solar cells

Abstract

AbstractLow–temperature deposition of Si for thin‐film solar cells has previously been hampered by low deposition rates and low material quality, usually reflected by a low open‐circuit voltage of these solar cells. In contrast, ion‐assisted deposition produces Si films with a minority‐carrier diffusion length of 40 μm, obtained at a record deposition rate of 0.8 μm/min and a deposition temperature of 650°C with a prebake at 810°C. A thin‐film Si solar cell with a 20‐μm‐thick epitaxial layer achieves an open‐circuit voltage of 622 mV and a conversion efficiency of 12.7% without any light trapping structures and without high‐temperature solar cell process steps. Copyright © 2001 John Wiley & Sons, Ltd.