Annealing-induced optical and sub-band-gap absorption parameters of Sn-doped CdSe thin films

作者：Kaur Jagdish; Tripathi S K^*

来源：Philosophical Magazine, 2016, 96(1): 45-57.

DOI：10.1080/14786435.2015.1122246

• Thin films
• CdSe
• thermal evaporation
• optical absorption
• annealing
• Urbach energy
• X-ray diffraction

Thin films of Sn-doped CdSe were prepared by thermal evaporation onto glass substrates in an argon gas atmosphere and annealed at different temperatures. Structural evaluation of the films was carried out using X-ray diffraction and their stoichiometry studied by energy-dispersive X-ray analysis. The films exhibit a preferred orientation along the hexagonal direction of CdSe. The optical transmittance of the films shows a red shift of the absorption edge with annealing. The fundamental absorption edge corresponds to a direct energy gap with a temperature coefficient of 3.34x10(-3)eVK(-1). The refractive index, optical conductivity and real and imaginary parts of the dielectric constants were found to increase after annealing. The sub-band gap absorption coefficient was evaluated using the constant photocurrent method. It varies exponentially with photon energy. The Urbach energy, the density of defect states, and the steepness of the density of localized states were evaluated from the sub-band-gap absorption.

• 出版日期2016-1-2