Influence of annealing temperature on some optical and structural properties of Cu2ZnSnS4 deposited by CZT co-electrodeposition coupled with chemical bath technique

Abstract

Copper indium gallium selenide (CIGS) is currently most efficient thin film solar technology in use but it is faced with problems of material scarcity and toxicity. An alternative earth abundant and non-toxic materials consisting of Cu2ZnSnS4 (CZTS) have been investigated as a replacement for CIGS. In this work, CZTS thin films deposited by low cost co-electrodeposition, at a potential of −1.2V, coupled with chemical bath techniques at room temperature and then annealed under sulphur rich atmosphere were investigated. CZTS thin film quality determination was carried out using Raman spectroscopy which confirmed formation of quality CZTS film, main Raman peaks at 288cm−1 and 338cm−1 were observed. Electrical characterization was carried out using four-point probe instrument and the resistivity was in the order of ∼10−4Ω-cm. The optical characterization was done using UV-VIS-NIR spectrophotometer. The bandgaps of the annealed CZTS film ranged from 1.45 to 1.94eV with absorption coefficient of order ∼104cm−1

in the visible and near infrared range of the solar spectrum were observed.