XPS analysis and luminescence properties of thin films deposited by the pulsed laser deposition technique

Abstract

This paper presents the effect of substrate temperature and oxygen partial pressure on the photoluminescence (PL) intensity of the Gd 2 O 2 S:Tb 3+ thin films that were grown by using pulsed laser deposition (PLD). The PL intensity increased with an increase in the oxygen partial pressure and substrate temperature. The thin film deposited at an oxygen pressure of 900 mTorr and substrate temperature of 900 • C was found to be the best in terms of the PL intensity of the Gd 2 O 2 S:Tb 3+ emission. The main emission peak due to the 5 D 4 -7 F 5 transition of Tb was measured at a wavelength of 545 nm. The stability of these thin films under prolonged electron bombardment was tested with a combination of techniques such as X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and Cathodoluminescence (CL) spectroscopy. It was shown that the main reason for the degradation in luminescence intensity under electron bombardment is the formation of a non-luminescent Gd 2 O 3 layer, with small amounts of Gd 2 S 3 , on the surface.