Thermal optimization of defected Cu2O photon-absorbing layer and the steady p-Cu2O/n-Si photovoltaic application

Abstract

Cuprous oxide (Cu2O), a far-reaching photon-absorption layer, is active in the field of solar cells and sensors. In this work, the Cu2O films prepared at low temperature by radio frequency (RF) magnetron sputtering holds a branch-like crystalline morphology, low optical transmittance and unsatisfactory carrier mobility. However, peroxidation will occur when thermal is excessive. By optimizing, the (111)-oriented monocrystal Cu2O films with trapping light structure are obtained through the rapid thermal annealing (RTA) process in N2 atmosphere, and the carrier mobility is escalated by five times to 11.75 cm2/v·s. On this basis, we construct an Au/p-Cu2O/n-Si/Al device and keep the leakage current standing at 1.81 × 10−9 A and the rectification ratio (IF/IR) reaching 177. Surprisingly, the unpackaged device still maintains a rectification ratio of 44 and a considerable leakage current even operating at 120 °C. Finally, we have measured the photovoltaic characteristic and provided some optimization strategies for power conversion efficiency.