Interference effects in photoluminescence spectra of Cu2ZnSnS4 and Cu(In,Ga)Se2 thin films

• DOI: 10.1063/1.4926857
• Publication Date: 2015-07-20T17:00:24Z
• Authors: J. K. Larsen; S.-Y. Li; J. J. S. Scragg; Y. Ren; C. Hägglund; M. D. Heinemann; S. Kretzschmar; T. Unold; C. Platzer-Björkman
• Keywords: Kesterite

Photoluminescence (PL) is commonly used for investigations of Cu2ZnSnS(e)4 [CZTS(e)] and Cu(In,Ga)Se2 (CIGS) thin film solar cells. The influence interference effects on these measurements is, however, largely overlooked in the community. Here, it demonstrated that PL spectra typical CZTS absorbers Mo/glass substrates can be heavily distorted by effects. One reason pronounced low reabsorption emission typically occurs below band gap. A similar situation gap graded CIGS where originates predominantly from minimum located at notch region. Based an optical model emitted a film, several approaches to reduce fringing are identified tested experimentally. These include use measured reflectance data, calculated function, high angles incidence during as well measurement polarized light near Brewster angle.