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. 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 E_g = 1.3 eV was determined from transmittance measurements.