Temperature dependent photoluminescence characteristics of nanocrystalline ZnO films grown by sol-gel technique

The structural as well as optical properties of nanocrystalline ZnO films, with hexagonal shaped particles of size 30-35 nm grown on p-Si (100) substrates by sol-gel technique, are investigated. Selected-area electron diffraction and X-ray diffraction patterns of annealed films reveal the formation of wurtzite structure. The mechanism of ultraviolet (UV) and green emission from ZnO thin films, post-annealed at various temperatures, is investigated using photoluminescence spectra. The oxygen content in annealed ZnO films plays an important role to suppress the green band emission. Temperature dependent photoluminescence spectra are recorded in the temperature range 10 K to 300 K to investigate different excitonic peaks in the UV-region.