STRUCTURE AND OPTICAL PROPERTIES OF NANOCRYSTALLINE ERBIA DOPED ZIRCONIA THIN FILMS

Abstract

Thin films of zirconia doped with erbia in the concentration range of 5 to 15% have been prepared on quartz substrates by an inorganic and aqueous sol–gel method. The films were crystalline, continuous and single phase as deposited, with a cubic fluorite structure and crystallite sizes of 8–10 nm as shown by X-ray diffraction. The films were annealed to 600 and 1050°C after deposition and found to be transparent in the region between 400 to 1100 nm, the crystalline structure becoming tetragonal at 1050°C with crystallite sizes of around 30–40 nm. The refractive index increased with increase in annealing temperature. There is a peak in the refractive index at a dopant concentration of 10% where it achieves a value of 1.88 at 700 nm. The optical absorption edge shows a similar peak at the same dopant concentration with a value of 5.65 eV.