Nature of electrical transport properties of nanocrystalline ZnIn2Se4 thin films

ZnIn2Se4 thin films were deposited on glass substrates by thermal evaporation technique. Some of ZnIn2Se4 films were annealed under vacuum at 623 K for 2 h. Atomic force microscope (AFM) images were analyzed for as-deposited and annealed films. The roughness degree of the film surface decreased under the influence of annealing. DC Electrical conductivity studied as a function of temperature. Two activation energies were determined that ΔE1 = 0.44 eV and ΔE2 = 0.65 eV. Using thermo-electric measurements, the thermoelectric power factor (P), carrier concentration (n) and mobility (μ) were calculated. Current density-voltage characteristics of Al/ZnIn2Se4/Al sandwich structure were examined. Different mechanisms were obtained; ohmic conduction mechanism at lower voltages and space charge limited conductivity (SCLC) mechanisms at higher voltages.