The growth of Cr~(4+):YAG and Cr~(4+):GGG thin films by pulsed laser deposition

摘要

The Cr,Ca:Y_(3)Al_(5)O_(12) (YAG) epitaxial thin films on YAG substrate have been fabricated by pulsed laser deposition (PLD) method. The chemical shifts of chromium ions in the Cr,Ca:YAG thin films is measured by X-ray photoelectron spectroscopy as a function of oxygen partial pressure in the PLD chamber. By measuring the fluorescence intensity of Cr~(4+) ions in Cr doped YAG thin films, it is found that the addition of Ca~(2+) ions as a charge compensator under oxygen background pressure increases the active Cr~(4+) ion fraction in the YAG thin film. The oxygen partial pressure of 2 mTorr is found optimum to maximize the Cr~(4+) number density in the Cr,Ca:YAG thin film. The Cr,Ca:GGG epitaxial thin film also shows the dependence of Cr~(4+) fluorescence on the oxygen partial pressure during deposition.