P-type Ca doped SrCu2O2 thin film: Synthesis, optical property and photovoltaic application

P-type transparent conducting oxide Sr0.9Ca0.1Cu2O2 (SCCO) films were prepared by pulsed laser deposition (PLD) technique on glass and n-Si (1 0 0) substrates. Some critical experiment factors were investigated, and it was found that well-crystallized, single phase SCCO films could be obtained with the substrate temperature higher than 350 °C, and the crystallinity was improved with the increase of laser energy fluence. Sr0.9Ca0.1Cu2O2/n-Si (SCCO/n-Si) heterojunction and prototype thin film solar cell were demonstrated respectively. Diode characteristic in the current–voltage response was observed and the ideality factor (n) of the diode was 3.7. The obtained n value is larger than unity due to structural imperfections of the layer and interface states. A prototype thin film solar cell with the best solar cell performance exhibits an open-circuit voltage (Voc) of 140 mV and a short-circuit current density (Jsc) of 0.072 mA/cm2 under irradiation of AM1.5 and 100 mW/cm2.

► Ca doped SrCu2O2 (Sr0.9Ca0.1Cu2O2) thin films were grown on Si substrate by pulsed laser deposition to construct heterojunctions.
► Diode characteristic was observed in the Sr0.9Ca0.1Cu2O2/n-Si heterojunction.
► The photovoltaic property of the heterojunction was investigated for the first time and an open-circuit voltage of 140 mV and a short-circuit current density (Jsc) of 0.72 mA/cm2 under irradiation of AM1.5 and 100 mW/cm2 was observed.