Low temperature photoluminescence characteristics of chemically synthesized indium doped zinc oxide nanostructures.

Photoluminescence (PL) emission and excitation (EPL) spectra of un-doped and indium (1%) doped 1D zinc oxide nanostructures are studied at different temperatures. The nanostructures reveal a blue emission band attributed to localized donor states. Indium doping enhances the blue emission. While at low temperatures (< 50 K) PL spectra are dominated by the emission attributed to the recombination of excitons bound to neutral donors (D(0),X), at higher temperatures (>100 K), defect related emissions in the visible range dominate over the excitonic emission. Temperature dependence measurements on the doped sample reveal that (D(0),X) emission energies obey the Varshni's formula with fitting constants alpha = 8.4 +/- 0.3 x 10(-4) eV/K and beta = 650 +/- 40 K. The (D(0),X) emission intensity decays exponentially with temperature.