Structural, optical and photo-electrical properties of nanocrystalline ZnSe thin films

摘要

Abstract Present paper reports the effect of deposition temperature on structure and electrical conduction mechanism of ZnSe thin films. Films have been fabricated on glass substrates using condensation technique. The depositions have been performed in presence of Ar at various substrate temperatures (298–373 K). X-ray diffraction (XRD) studies reveal hexagonal structure with texture changing from (002) to (102) on increasing substrate temperature. The crystallite size (6.1–8.4 nm), strain (− 0.0133 to − 0.00748 lin_(−2) m_(−4)), dislocation densities (1.857 × 10_(16)–1.015 × 10_(16)lin m_(−2)) and stacking fault probability (0.0038–0.0041) have been calculated from XRD data. The optical gap (2.75–3.00 eV), refractive index (2.38–2.48) and ionicity (0.425–0.446) have been calculated using transmission measurements. The dark-conduction and photo-conduction behaviours have been studied in temperature range 253–358 K. The two activation energies of dark conduction have been explained using different models. The conduction mechanism has been identified based on Seto’s model of thermionic emission. The barrier height (0.17–0.28 eV), impurity concentration (1.26 × 10_(20)–3.18 × 10_(20)cm_(−3)) and surface states density (1.05 × 10_(14)–2.15 × 10_(14)cm_(−2)) have also been calculated.