Crystallization and spectroscopic properties of electron-beam-deposited, chromium-doped, forsterite films

A sol-gel prepared, chromium-doped, magnesium- and silicon-containing oxide mixture was used as a target material for the electron-beam deposition of 1.2 mu m thick chromium-doped forsterite films onto single-crystal quartz substrates. The stoichiometry of the target materials was adjusted to compensate for the disparate volatilities of the component oxides. X-ray diffraction revealed that the as-deposited films were amorphous, and the refractive indices of the films revealed that they were near full density. seating the films to 650 degrees C produced isolated crystallites of forsterite that ranged in size from 50 to 250 nm in an amorphous matrix (by TEM). Only films that had been heated to 725 degrees C and above revealed Cr4+ emissions.