Temperature dependence and the effect of hydrogen peroxide on ITO/poly-ZnO Schottky diodes fabricated by laser evaporation

• Highly c-axis-oriented ZnO thin films were fabricated using a continuous-wave (CW) carbon dioxide (CO2) laser.
• Grazing incidence X-ray diffraction (GIXRD) analysis revealed a peak (111) for zinc peroxide (ZnO2) at low temperature.
• ZnO2 layer resulting from the H2O2 treatment was further characterized by examination of the core O1s XPS profiles.
• A trade-off relationship between the film quality and the degree of oxidation was observed via I–V measurements.

Transparent and efficient poly-ZnO ultraviolet Schottky diodes grown at different temperatures with indium-tin-oxide (ITO) as the metallic contact layer were fabricated with hydrogen peroxide (H2O2) applied as a surface treatment at 70 °C for 20 min. Analysis via field-emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS) demonstrated that the ZnO films underwent gradual oxidation and that H2O2 treatment resulted in an interfacial ZnO2 layer that covered the ZnO surface. I–V measurements indicated that the ideality factor and the Schottky barrier height improved with increasing shunt resistance, and the trade-off between film quality and the degree of oxidation revealed that films grown at 400 °C exhibited the best diode characteristics.