Photoluminescence of metal oxides coated porous silicon
Abstract
Photoluminescence (PL) emission of porous silicon (PSi) coated with various metal oxides was investigated. PSi was fabricated through electrochemical etching in HF-ethanol solution. Metal oxides such as SnO2 , ZnO and CuxO were deposited on porous layer via spray pyrolysis. Shift in interference peaks of reflectance spectra confirmed that the effective refractive indices of each sample changes as metal oxides were added. Different PL spectra were observed on the three samples. A shift in longer wavelength due to oxide defects was observed for SnO2/PSi and ZnO/PSi since these are transparent at visible wavelengths. CuO/PSi PL peaks dropped and shifted towards longer wavelength due to absorption characteristics contributed by CuO.