Structural, Optical and Electrical Conductivity Properties of Stannite Cu2ZnSnS4

A precursor powder was obtained from drying the solutions of a mixture of different ratios of Cu, Zn and Sn chloride and thiourea. The Cu2ZnSnS4 (CZTS) samples were prepared from thermal decomposition of the corresponding precursors in vacuum, and were then characterized using scanning emission microscopy, energy dispersive x-ray analysis, x-ray powder diffraction and Raman scattering. According to x-ray diffraction analysis, all the synthesized samples had a tetragonal structure of space group I4¯2m\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$I\overline{4} 2m$$\end{document}. The electrical properties of the CZTS samples were investigated in the temperature range of 10–325 K. The charge carrier concentration was measured to be about p = 1 × 1016 cm−3. A crossover from a nearest-neighbor hopping conduction mechanism at high temperatures (T > 150 K) to a Mott variable-range hopping conduction mechanism at low temperatures (T < 150 K) was observed. The activation energies of the CZTS samples were calculated for the low and high ranges of temperature. A thin film on quartz substrates was obtained using magnetron sputtering, for which a band gap of Eg = 1.3 eV was determined from transmittance measurements.