White-Light Emission from Annealed ZnO:Si Nanocomposite Thin Films

TL;DR

This study demonstrates that annealing ZnO:Si nanocomposite thin films enhances their photoluminescence, leading to broad-spectrum white light emission due to the formation of Zn2SiO4 compounds around ZnO nanoclusters.

Contribution

First demonstration of white light emission from annealed ZnO:Si nanocomposites via formation of Zn2SiO4 compounds.

Findings

Enhanced PL intensity and broadening after annealing

Observation of UV, red, and orange peaks at 310, 570, and 640 nm

Formation of Zn2SiO4 shell around ZnO nanoclusters

Abstract

As grown ZnO:Si nanocomposites of different compositional ratios were fabricated by thermal evaporation techniques. These films were subjected to post deposition annealing under high vacuum at a temperature of $\rm 250C^o$ for 90min. The photoluminescence (PL) spectra of annealed samples have shown marked improvements both in terms of intensity and broadening. For the first time in ZnO:Si nanocomposite films we see huge UV, red and orange peaks at 310, 570 and 640nm. Structural and Raman analysis show formation of a Zn-Si-O shell around ZnO nano clusters wherein on heating $\rm Zn_2SiO_4$ compound forms. The new emissions are due to $\rm Zn_2SiO_4$ which completes white light spectrum.