Influences of oxygen contamination on evaporated poly-Si thin-film solar cells by solid-phase epitaxy

Abstract

The influences of the oxygen contaminations on the crystal quality and performances of the evaporated polycrystalline silicon (poly-Si) thin-film solar cells prepared by solid-phase epitaxy were investigated by applying different deposition rates and base pressures. The experimental results show that although the evaporated poly-Si thin-film solar cell obtained at high base pressures (9.33 × 10- 5 Pa) and high deposition rate (300 nm/min) has small amount of SiO2 precipitations, it still shows the similar good material quality and performances as the cell prepared at low base pressure (1.33 × 10- 6 Pa) and high deposition rate (300 nm/min) with oxygen interstitials. On the other hand, the poly-Si thin-film solar cell deposited at low base pressure (1.33 × 10- 6 Pa) and low deposition rate (50 nm/min) has large amount of SiO2 precipitations and resulting worse material quality and hence cell performances. Therefore, the high deposition rate is desirable to maximize the solar cell performance, as well as the throughput. It is a more influential factor than the base pressure. © 2009 Elsevier B.V. All rights reserved.