Structural, optical, and electrical properties of Cu$_{2}$SnS$_{3}$ thin films produced by sol gel method

The structural, optical, and electrical properties of $p$-type Cu$_{2}$SnS$_{3}$ thin films produced by the deposition of a dimethylsulfoxide-based sol gel solution using the centrifugation on substrates with subsequent heat treatment of the layers formed have been studied. The conditions of formation of the films using low-temperature short-time treatments in open atmosphere and a final annealing in a low vacuum (0.1 Pa) have been analyzed. The crystallite sizes $D\sim$ 42 nm in the polycrystalline films have been found using X-ray phase analysis. Their compositions have been confirmed using the Raman spectra and the energy-dispersive X-ray analysis. The optical forbidden band width of direct allowed ($E_{g}^{d}\approx$ 1.25 eV) and direct forbidden ($E_{g}^{df}\approx$ 0.95 eV) optical transitions have been determined as a result of the light transmission and absorption. Based on the study of the electrical properties using a model of polycrystalline materials, the validity of the produced films with resistivity $\rho\approx$ 0.21 $\Omega$ $\cdot$ cm, the hole concentration $p_{0}\approx$ 1.75 $\cdot$ 10$^{19}$ cm$^{-3}$, and the effective mobility $\mu_{p}\approx$ 1.67 cm$^{2}$/(V $\cdot$ s) for manufacturing solar cells.