Studies on Semiconductor Semiconductor ZNO SI Nanocomposites and their Various Properties

Abstract

Nanocomposite thin films of Zinc Oxide (ZnO) and Silicon (Si) have newlinebeen fabricated by thermal evaporation method at room temperature. The newlinegrain size of ZnO nanoclusters was found to lie in few nanometres range. newlineWith the structural, morphological and chemical analyses, dispersion of ZnO newlinenanograins in the amorphous background of Silicon was established. As newlinegrown films of ZnO:Si were found to be stable over a period of two years and newlinehad shown little or no agglomeration. newlineAs deposited films had shown good photoluminescence (PL) with peaks newlinecentered at around 370, 410, 470 and 520 nm. Besides these, a weak peak newlineat 620 nm was also noticed. While the emissions at 370 and 520 nm are newlinecommonly observed in the PL spectra of ZnO, 410 and 470 nm peaks are newlinerelatively new. Broadening observed due to 370 and 520 nm emissions has newlinebeen related to the ratio of Wurtzite (crystalline, free from defects) and defect newlineincorporated ZnO respectively. Occurrence of the peaks in blue region (i.e 410 newlineand 470 nm) has been attributed to the interface of ZnO and Silicon species. newlineThough both the peaks are associated to the heterogeneous boundary, the newlinephysics behind their origin is different. Whereas 470 nm is related to the newlineinterface between ZnO and Silicon, the 410 min comes from a shell around the newlineZnO clusters. This shell is chemically and structurally different from the core newlineand the matrix and is suggested to consist of Zn-Si-O linkages. Systematic newlineinvestigations reveal the presence of a suitable compositional ratio of ZnO to newlineSilicon (for a given thickness), which inturn would influence the grain size (R) newlineand the number of grains (N), is critical for the coexistence of all four peaks. newlineThe grain size and number of grains was also observed to be dependant on newlinethe thickness of the ZnO:Si nanocomposite films fabricated with the same newlineZnO:Si compositional ratio.