Fundamental optical absorption edge of undoped tetragonal zirconium dioxide

The high-frequency optical absorption edge of pure tetragonal ZrO2, isolated in a ZrO2-Al2O3 nanolaminate film structure, was determined using transmission spectrophotometry. The functional dependence of the absorption coefficient on photon energy shows two interband transitions: an initial indirect transition at 5.22 eV (i.e., the band gap) followed by a direct transition at 5.87 eV. The edge structure is associated with O 2p-->Zr 4d electron states and discussed in terms of ab initio calculations reported in the literature. (C) 2003 American Institute of Physics.