Films of (Gd_(1-x)Tb_xO_2S Solid Solutions Produced by Oxide Sulfidation in NH_4SCN Vapor and Their Optical Properties

摘要

(Gd1- xTbx)(2)O-3(x= 0.04-0.22) films 115 to 150 nm in thickness have been grown on Si and SiO(2)substrates by metal organic chemical vapor deposition (MOCVD) using Ln(dpm)(3)precursors. After annealing in air at 800 degrees C for removing carbon-containing impurities, the films were sulfided in NH4SCN vapor at temperatures from 700 to 1000 degrees C in an Ar atmosphere until the formation of (Gd1 -xTbx)(2)O2S oxysulfides. The surface of the films is formed by grains 60 to 200 nm in size. The measured refractive index of the films is 2.2-2.4 and their estimated optical band gap (E-g) is 4.7-5.0 eV. The optical transmission of the films in the visible spectral region (400-750 nm) reaches 78-84%. The highest photoluminescence (PL) intensity in the oxysulfide films produced under identical conditions has been observed atx= 0.05. The blue component of their PL decreases with increasing terbium content and the emission shifts to the green spectral region.