Abstract
The polycrystalline zinc aluminum oxide (P-ZnAlO) composite films are deposited on Si for different (2 hrs, 3 hrs and 4 hrs) evaporation time (ED by thermal evaporator. The XRD patterns confirm the development of different diffraction peaks related to ZnO (101, ZnO (002), ZnO (100) and Al2O3 (400) phases. The peak intensity of ZnO (100) plane is maximum when the film is deposited for 4 hrs ET. The crystallite size of Al2O3 (400) and ZnO (002) plane is found to be 25.43 nm and 11.58 nm whereas it is 14.72 nm for Al2O3 (400) plane and 33.65 nm for ZnO (100) plane for 3 and 4 hrs ET respectively. The decrease in crystallite size of Al2O3 (400) plane is associated with the orientation transformation of ZnO phase and rearrangement of crystallites of Al2O3 (400) phase with increasing ET. The orientation transformation of ZnO phase is associated with the increase of ET. The dislocation density observed in different planes decreases with the increase of crystallite size. The SEM microstructure shows that the formation and growth of nano-particles having various shapes, sizes and distribution are associated with the increase of ET. The EDS spectrum confirms the presence of Zn, Al and O in the deposited P-ZnAlO composite films. The optical energy band gap of P-ZnAlO film varies from 3.39 eV to 3.9 eV with the increase of ET.