Epitaxially grown crystalline silicon thin-film solar cells reaching 16.5% efficiency with basic cell process

Abstract

We report about the current performance of crystalline silicon thin-film (cSiTF) solar cells that are a very attractive alternative to conventional wafer-based silicon solar cells if sufficiently high cell efficiencies are achieved at acceptable cost of production. Applying a standard cell process (diffused POCl 3 emitter, front contacts by photolithography, no surface texture) to thin-films deposited with a lab-type reactor, specifically designed for high-throughput photovoltaic applications, on highly-doped Cz substrates we routinely obtain efficiencies above 16%. On 1 Ω cm FZ material substrates we reach efficiencies up to 18.0%, which is among the highest thin-film efficiencies ever reported. Additionally, a comparison to microelectronic-grade epitaxially grown cSiTF material underlines the excellent electrical quality of the epitaxial layers deposited.