Research on Cu2ZnSnTe4 crystals and heterojunctions based on such crystals

Abstract

The paper reports on the results of the studies of magnetic, kinetic and optical properties of Cu₂ZnSnTe₄ crystals. The Cu₂ZnSnTe₄ crystals showed diamagnetic properties (the magnetic susceptibility almost independent of the magnetic field and temperature). The Cu₂ZnSnTe₄ crystals possessed p-type of conductivity and the Hall coefficient was independent on temperature. The temperature dependence of the electrical conductivity of the Cu₂ZnSnTe₄ crystal shows metallic character, i.e. decreases with the increase of temperature, that is caused by the lower charge carrier mobility at higher temperature. Thermoelectric power of the samples is positive that also indicates on the prevalence of p-type conductivity. Heterojunctions n-TiN/p-Cu₂ZnSnTe₄, n-TiO₂/p-Cu₂ZnSnTe₄ and n-MoO/p-Cu₂ZnSnTe₄ were fabricated by the reactive magnetron sputtering of TiN, TiO₂ and MoOx thin films, respectively, onto the substrates made of the Cu₂ZnSnTe₄ crystals. The dominating current transport mechanisms in the n-TiN/p-Cu₂ZnSnTe₄ and n-TiO₂/p-Cu₂ZnSnTe₄ heterojunctions were established to be the tunnel-recombination mechanism at forward bias and tunnelling at reverse bias.