Role of MoS2 and MoSe2 thin films in performance of new-generation CMTSe solar cells fabricated by a quasi-co-evaporation method

Abstract

In this paper a new quasi-co-evaporation method is used to fabricate the absorber layer of CMTSe solar cells. The crystallographic and morphological properties of the fabricated layer are experimentally investigated by XRD and SEM-EDS analyses, while also studying the role of the intermediate layer formed on Mo/CMTSe surface using SCAPS-1D. The SEM and XRD results show integrated growth of the CMTSe absorber layer, showing a stannite crystal structure with optimal intensity, which indicates the achievement of phase-pure growth and crystal structure with the desired crystal quality and optimal composition. The crystallite size and lattice strain are calculated to be 60 nm and 0.8 % based on the Scherrer equation and applying the Williamson-Hall methods, respectively. The band gap of the CMTSe absorber layer is obtained to be 1.25 eV using Tauc plot derived from DRS analysis. By inserting structural parameters of the fabricated layer into the SCAPS-1D simulation, the role of MoS₂ and MoSe₂ interface layers in the solar cell performance is investigated. In general, while the n-type MoS₂ and MoSe₂ layers plays a destructive role in the cell performance, the p-type MoS₂ and MoSe₂ layers improve it by enhancing the internal field. The best parameters (V_oc: 0.75 V, J_sc: 45.23 mA/cm², FF: 76.2 %, and Eff: 26.1 %) are obtained for the solar cell with p-MoSe₂ interlayer.