Effects of copper excess and copper deficiency on the structural and electrical properties of bulk CuxSnSe3 with x=1.6–2.2

•CuxSnSe3 (CTSe) bulks with 1.6≤x≤2.2 were prepared by reactive sintering.•Cu2SnSe3 with np of 1.02×1018 cm−3 and μ of 225 cm2/V/s had highest σ of 39 S/cm.•Cu1.6SnSe3 with np=5.0×1017 cm−3 and μ=11 cm2/V/s had lowest σ=0.90 S/cm.•Lower np at CTSe at x=1.6 is related to the formation of the Sn-to-Cu defect.•The drop in np for CTSe at x=2.2 indicates VSn4− dominates over CuSn3− defect.

Effects of the Cu variation on the morphological, structural, and electrical properties of bulk CuxSnSe3 (CTSe) with x=1.6–2.2 have been investigated. Dense CTSe pellets with grains of 3–4 µm were obtained after sintering at 550 °C. All CTSe pellets showed a dominant p-type behavior. CTSe at x=2.0 with a hole concentration (np) of 1.02×1018 cm−3 and Hall mobility (μ) of 225 cm2/V/s had a highest conductivity (σ) of 39 S/cm. CTSe at x=1.6 with np of 5.0×1017 cm−3 and of 11 cm2/V/s had a lowest of 0.90 S/cm. The explanation, based upon vacancies and antisite defects, for the changes in electrical property with the Cu content is supported by the data from lattice parameter. The study in bulk properties of CTSe and its defects is helpful for selecting the suitable absorber composition to fabricate thin film solar cells.

Graphical abstractCu2SnSe3 is an absorber candidate for solar cells. The Cu stoichiometry on electrical properties, which is important for CIGS and CZTS, is investigated and the Cu-deficiency composition is recommended.Figure optionsDownload full-size imageDownload as PowerPoint slide