Optical And Electrical Characterization Of Znse-Cuxoy Thin Films For Solar Cell Applications

ABSTRACT

Solar energy which is a free and abundant form of energy has the potential to provide sufficient power to the growing number of industries and population especially in the developing world. Its maximum exploitation has however been hindered by the high cost of silicon based solar cells which currently dominate the market. It has been reported that copper based thin film solar cell technology is known to be 40% cheaper than silicon based solar cells. In order to effectively exploit solar energy, research into new materials for production of cheaper and efficient solar cell must be intensified. In this study optical and electrical characterization of Copper Oxide and Zinc Selenide thin films for solar cell application were investigated. Deposition of CuxOy using an Edward Auto 306 RF/DC Magnetron DC magnetron sputtering technique is reported. ZnSe was prepared by the vacuum evaporation technique. The optical properties were studied using the UV-VIS NIR Spectrophotometer Solid State Spec 3700 DUV optical spectrum analyzer. The optical band gap of CuxOy was found to be in the range 1.93-2.34 eV while that of ZnSe lies between 2.32 and 2.49 eV. The sheet resistivity of the films was measured using the four point probe technique. For CuxOy the sheet resistivity lies between 36.25 and 53.92while that of ZnSe lies between 86.95 and 102.85. The electrical properties of the fabricated pn junction were investigated using a solar simulator. The open circuit voltage (Voc,), short circuit current ( Isc ), Fill Factor (FF) and efficiency ( ) of the pn junction were found to be 0.59 V, 1.06 mA, 66.6 % and 0.42 % respectively. CuxOy-ZnSe exhibit photovoltaic behaviour and are suitable for solar cell applications. Further research to improve the cell efficiency is recommended. cm cm 