Intense UV-Visible-IR Adjustable Photoluminescence from Silicon-rich Oxynitride Layers Prepared by Plasma Enhanced Chemical Vapor Deposition

Abstract

ABSTRACTThe intense UV-visible-IR adjustable light emissions from silicon-rich oxynitride thin films without any thermal annealing were observed at room temperature under a 325 nm He-Cd laser excitation. The silicon-rich oxynitride thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) with the mixture of 5% Ar diluted silane and nitrous oxide gases. The strong naked-eye recognizable photoluminescence (blue-white-red) could be adjusted by changing the process gas flow ratio τ =([SiH4]/[N20]). To the best of our knowledge, intense and adjustable UV-blue light emissions in the as-deposited thin films are first reported in this work. The Fourier Transform infrared (FTIR) spectroscopy was applied to investigate the microstructure-bonding configurations, in which silicon polysilane related bonding at 830-890 cm' present that silicon complex, exists along with the Si-O-Si bonding. X-ray photoelectron spectroscopy was used to investigate the binding configuration, the binding energy of Si 2p appearing at 99.3 eV was indicative of formation of the silicon clusters. As a consequence, we suppose that the visible-IR lights emissions might possible be strongly related to silicon clusters formation in the films and the intense UV emissions might come from the oxygen-related defects.