Open air annealing effect on the electrical and optical properties of tin doped ZnO nanostructure

Transparent conducting undoped and tin doped ZnO multilayer films were deposited by sol-gel method. Effect of open air annealing on different parameters like grain size, carrier density, band gap, resistivity, refractive index and extinction coefficient were investigated. Films were deposited on glass and silicon substrate by keeping doping concentration 4 at%. It was observed that tin doping reduces resistivity from 194.6 Ω cm to 3.11 Ω cm. Optical transmission spectra exhibit transmittance above 88% in visible range. Maximum carrier density of 11.9 × 1018 cm−3 and band gap of 3.24 eV was estimated at 375 °C. Scanning Electron Microscopy showed homogenous worm like morphology. Atomic force microscopy revealed pyramid shaped nanostructure of tin doped ZnO.

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► Tin doped ZnO nanostructure films were deposited by sol-gel method.
► Annealing at 375 °C reduced resistivity from 194.6 Ω cm to 3.11 Ω cm.
►  Maximum carrier density of 11.9 × 1018 cm−3 and band gap of 3.24 eV was estimated.
► Atomic force microscopy reveals pyramid shaped nanostructures of tin doped ZnO.