In this study, the electrical and optical properties of Zn doped tin oxide films prepared using sol-gel spin coating process have been investigated. The SnO 2 : Zn multi-coating films were deposited at optimum deposition conditions using a hydroalcoholic solution consisting of stannous chloride and zinc chloride. Films with Zn doping levels from 0-10 wt% in solution are developed. The results of electrical measurements indicate that the sheet resistance of the deposited films increases with increasing Zn doping concentration and several superimposed coatings are necessary to reach expected low sheet resistance. Films with three coatings show minimum sheet resistance of 1⋅ ⋅479 kΩ Ω/ in the case of undoped SnO 2 and 77 kΩ Ω/ for 5 wt% Zn doped SnO 2 when coated on glass substrate. In the case of single layer SnO 2 film, absorption edge is 3⋅ ⋅57 eV and when doped with Zn absorption edge shifts towards lower energies (longer wavelengths). The absorption edge lies in the range of 3⋅ ⋅489-3⋅ ⋅557 eV depending upon the Zn doping concentration. The direct and indirect transitions and their dependence on dopant concentration and number of coatings are presented. Keywords. Transparent conducting oxides; electrical and optical properties; tin oxide films; zinc doping; spin coating.

A theory of free carrier absorption is given for GaAs/GaAlAs quantum wells when the carriers are scattered by confined LO phonons. The Huang and Zhu approximation for the confined phonon modes is used. The absorption coefficient is calculated and is found to have, broadly, features similar to the calculations with bulk phonons. The well width dependence of absorption is found to be opposite to that exhibited by scattering rates.

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The effects of electron beam irradiation on the electrical and the optical properties of zinc oxide (ZnO) and aluminum-doped zinc oxide (ZnO:Al) thin films, prepared by the sol-gel technique, were investigated. The grain size, surface morphology, sheet resistance, optical constants, absorption edge, and direct and indirect optical band gaps of these films were analyzed before and after exposure to electron beam. The decrease in the structural homogeneity and the crystallinity of the films after exposure to electron irradiation is observed. The irradiation causes increase in the sheet resistance and blueshift in the absorption edge for both ZnO and ZnO:Al films. The change in carrier concentration due to doping as well as the exposure to electron beam are responsible for the modified electrical and optical properties.

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