SYNTHESIS AND CHARACTERIZATION OF CIGS THIN FILMS DEPOSITED BY PULSE LASER DEPOSITION FOR SOLAR CELL APPLICATION

Abstract

Solar cells act as a most direct device for converting solar energy in to electrical energy. Thin films solar cells technology has been growing its importance for last one decade. This technology allows the fabrication of less expensive modules and has good power conversion efficiency. Among thin film solar cells (CIGS) have the highest conversion efficiency till date, reaching 20.3% on the laboratory scale. CIGS thin-film solar cells are the most promising cheap solar cells because of its low cost, stable performance. strong resistance to radiation. and high absorption coefficient. The present study includes the development of efficient absorbing layer with suitable metal contact for thin films solar cells application. In the first part of investigation, Low resistance molybdenum thin film deposited on soda lime glass by DC magnetron sputtering have been studied. The Mo thin films specially used as a back contact material for a CIGS solar cells. The structural, morphological electrical and Optical properties of Mo thin film are being characterized various instruments and investigated as like XRD, FE-SEM, AFM, four point probe method and UV-vis NlR spectrophotometer respectively. Polycrystalline Mo thin films with preferred orientation along the (110) plane has been achieved. After analysis the optimum deposition parameters, molybdenum thin films as back contact layer with different thickness have been developed. In the second part of the investigation, CIGS thin film have been deposited on soda lime glass substrate at different substrate temperature and laser energy by PLD technique. The effect of substrate temperature and laser energy on structural, optical and electrical properties of CIGS thin films has been investigated by X-ray diffractometer (XRD), Field emission scanning electron microscope (FE-SEM), Atomic force microscopy (AFM). UV-vis NIR spectrophotometer and electrical measurement unit. XRD study reveals that all deposited CIGS films are polycrystalline in nature and have tetragonal phase. Surface of developed film is found to be sufficiently smooth to use as an absorbing layer. Absorbance of CIGS films is found to increase with increase laser energy. Absorption co-efficient is found to be higher than 105 cm1 for higher energy photon.