Size and Defect related Broadening of Photoluminescence Spectra in ZnO:Si Nanocomposite Films

摘要

Nanocomposite films of Zinc Oxide and Silicon were grown by thermalevaporation technique using varying ratios of ZnO:Si in the starting material.Analysis reveal the role of ZnO and amorphous silicon interface in contributingto relatively less common blue photoluminescence emissions (at $\sim$ 400 and470nm). These blue peaks are observed along with the emissions resulting fromband edge transition (370nm) and those related to defects (522nm) of ZnO.Careful analysis shows that along with the grain size of ZnO, a suitablecompositional ratio (of ZnO to silicon) is critical for the coexistence of allthe four peaks. Proper selection of conditions can give comparablephotoluminescence peak intensities leading to broad-band emission.