The investigation of some structural, optical and schottky diode properties of ZnO microrods prepared by spray pyrolysis method

In this study, ZnO microrods were grown on ZnO seeded glass and SnO2 coated substrates by the spray pyrolysis method. Some structural, optical and electrical properties of these ZnO microrods were investigated. It was observed that ZnO microrods had a polycrystalline and hexagonal structure. From the XRD diffraction pattern, it was obtained that ZnO sample had a (002) peak in the highest intensity. The a and c lattice paramater values of ZnO microrods were found to be 3.24 Å ve 5.19 Å, respectively. As SEM images were investigated, it was seen that ZnO rods homogeneously distributed in the ZnO host matrix and also they vertically grew on the substrate surface. From optical measurements, the band gap value of ZnO microrods was determined to be 3.22 eV. The forward and reverse bias I-V characteristics of In-Ga/SnO2/ZnO/Ag structure were studied between 125 and 300 K with a step of 25 K. From obtained results of forward bias I-V characteristics where thermionic emission theory was applied, zero bias barrier height increased with an increase of temperature whereas ideality factor decreased. In addition, it was observed that ln(Io/T2) vs. q/kT curve deviated from the linearity. From this curve, the barrier height and Richardson constant values were determined as 0.32 eV and 3.27x10-9 A.cm-2.K-2, respectively. By means of vs. q/kT curve, mean barrier height and Richardson constant values were found to be 0.88 eV and 27.5 A.cm-2.K-2, respectively.Key Words: In-Ga/SnO2/ZnO/Ag Schottky structure; Current-transport mechanism; Barrier height