Investigation of the resistivity of molybdenum diselenide prepared with varied sodium content

Thin film solar cells made of Cu(In,Ga)Se 2 or Cu 2 ZnSnSe 4 tend to form a chalcogen phase with the molybdenum back contact during absorber processing. The impact on solar cell performance is manifold and depends on the MoSe 2 layer properties. In this study, the characteristics of MoSe 2 layers produced from Mo layers with varied Na content were investigated. The formation of MoSe 2 for all samples was confirmed by Raman spectroscopy and X-ray diffraction (XRD). Scanning electron microscopy (SEM) shows a decrease in thickness of the MoSe 2 layers with increased Na content. Results of glow discharge optical emission spectroscopy (GDOES) demonstrate that Na is incorporated in the Mo layers of the samples, while Na accumulates near the surface of the samples and at the MoSe 2 /Mo interfaces. Measurements of the electrical resistivity of the MoSe 2 layers give a range of 270–600 Ωcm for all samples, confirming a low impact of Na on the electrical characteristics of the MoSe 2 layers.