Preparation and characterization of Cu:Co3O4/Si heterojunction prepared by spray pyrolysis

Undoped and Cu doped cobalt oxide thin films with (x= 1, 3, 5, 7, and 9)% were prepared by spray pyrolysis at substrate temperature (350)degrees C. Structural and optoelectronic properties of thin films were studied by X-ray diffraction XRD, Atomic Force Microscope AFM, current- voltage (I-V) and capacitance- voltage (C-V) measurement. X-ray diffraction results revealed that all films consist of single Co3O4 phase with preferred orientation (111) and cubic spinel structure. AFM micrographs indicated that the grain size decrease with increasing Cu doping. Current transport properties of the p-Cu:Co3O4/n-Si heterojunctions are investigated by currentvoltage measurements in dark and illumination with different incident power. The ideality factor were found to be strongly depending on Cu doping, there is an increase in the ideality factor with increasing Cu doping. In part of C-V measurements, built-in potential value were found to decrease with increasing of Cu. The higher spectral responsivity of the junction was 54 A/W at (600-700) nm wavelength for copper ratio 9%. (C) 2017 The Authors. Published by Elsevier Ltd.