Optical and electrical characterization of ZnO/CuO heterojunction solar cells

This paper reports the fabrication and characterization of nontoxic heterojunction of ZnO/CuO. The films were characterized through X-ray diffraction, UV spectroscopy and field emission scanning electron microscope (FESEM). The valence and conduction band edges were measured through Photo-Electron spectroscopy in air. The electrical parameter for FTO/ZnO/CuO/In heterojunction diode such as ideality factor, barrier height, and series resistance were calculated by using conventional forward bias I-V characteristics and also verified with the help of Cheung method. The high value of ideality factor was attributed to high series resistance, defects, other phases of CuO and recombination at interface and within bulk. The double logarithmic graph of current and voltage showed that the transport mechanism is due to the space charge limited current and trapped charge limited current. Photovoltaic parameters Voc of ∼190 mV and Jsc of ∼0.40 mA/cm2 of FTO/ZnO/CuO/In heterojunction were recorded.