Improvement in optoelectronics and photovoltaic properties of p-Co₃O₄/n-ZnO hetero-junction: effect of deposition time of sprayed Co₃O₄ thin films

Spinel thin films Co3O4 have been deposited at a temperature of approximately 400 C-degrees using spray pyrolysis. The testimony process was carried out with different deposition times (4, 5, 6, and 8 min), indicating that the films were grown for varying durations. The objective of varying deposition times of the thin films of Co3O4 was to optimize the fabrication of a hetero-junction between Co3O4 and ZnO. XRD, SEM and Raman investigations showed that pure cubic Co3O4 with an irregular spindle shaped particles have been successfully obtained. The films' thickness increased under prolonged preparation times leading to a denser surface. The optical measurements revealed that the thin layer with a deposition time of 8 min attained a total absorbance of 98% in the apparent spectrum with a band gap of 1.27 eV. The I-V characteristics recorded of FTO/ZnO/Co3O4/Au cells showed that all devices exhibiting a rectifying behavior with a perfect factor that varies between 3.87 and 1.64. Our results suggest that Co3O4 at 8 min with a carrier density of 2.414 x 10(14) cm(-3) and high absorbance is potentially a competitive hole transport material in spinel solar cells, and, the recorded characteristics of the photovoltaic phenomenon were noted a short circuit current of 1.302 mA, an open circuit voltage of 369 mV and a fill factor of 32%.