Polycrystalline thin-film CuInSe₂/CdZnS solar cells

Abstract

The fabrication and properties of polycrystalline, CuInSe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> thin-film solar cells based upon a heterojunction device structure of P-type CuInSe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> and N-type CdS or mixed CdZnS are described. A photovoltaic conversion efficiency of 11 percent is reported for a CuInSe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> / CdZnS cell of 1-cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> area when tested under simulated AM1 illumination (ELH lamp). While the highest efficiency cells have been prepared on Mo-metallized, polycrystalline alumina substrates, good cell performance is also presented for cells fabricated on low-cost glass substrates. The vacuum deposited selenide and sulfide films are reported to exhibit strong columnar growth features throughout the critical junction region. The spectral response of the cells is described as being relatively flat from 1100 to 600 nm with very high quantum yields(> 0.8). Photoluminescence emission data on the CuInSe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> thin-film excited with a He-Ne laser is presented. In general, selenide films producing a good cell performance are reported to exhibit spectra with two or three major broad-band emissions.