Exploring the possibility of semiconducting BaSi2 for thin-film solar cell applications

Semiconducting BaSi2 has attractive features for thin-film solar cell applications because both a large absorption coefficient and a long minority-carrier diffusion length can be utilized. In this article, we explore the possibility of semiconducting BaSi2 films for thin-film solar cell applications. Recent experimental results on the optical absorption coefficient, minority-carrier diffusion length, and minority-carrier lifetime in undoped n-BaSi2 films are presented. After that, the photoresponse spectra are calculated for a BaSi2 p(+)n abrupt homojunction diode based on the one-dimensional carrier continuity equation using previously reported experimental values. The individual contributions of the three layers, that is, the neutral p(+)-type layer, the depletion region, and the neutral n-type layer, to the total photoresponse are discussed. The photoresponse depends on parameters such as layer thickness, minority-carrier diffusion length, and surface recombination velocity. We further estimate the photocurrent density and the open-circuit voltage under AM 1.5 illumination. (C) 2015 The Japan Society of Applied Physics