Effect of background atmosphere and substrate temperature on SrO:Bi3+(0.2 mol%) thin films produced using pulsed laser deposition with different lasers

Abstract

SrO:Bi3+ (0.2 mol%) phosphor thin films were grown by pulsed laser deposition (PLD) on Si (100) substrates in vacuum and different O2 atmospheres at different substrate temperatures using a Nd:YAG laser (266 nm) with energy 33.3 mJ/pulse, a KrF laser (248 nm) with energy 300 mJ/pulse or a ArF laser (193 nm) with energy 150 mJ/pulse. The microstructure and photoluminescence (PL) of these films were found to be highly dependent on the background atmosphere and substrate temperature. X-ray diffraction (XRD) analysis showed that the SrO:Bi3+ (0.2 mol%) films varied from amorphous to highly crystalline depending on the deposition conditions. Atomic Force Microscope results showed that the surface roughness decreased as the substrate temperature increased. The main PL emission peak position of the thin films showed a shift to shorter wavelengths at 427 nm, when compared to the powder (445 nm). The difference in wavelength was attributed to the Bi3+ ions, which are very sensitive towards the environment. Time of flight secondary ion mass spectroscopy depth profiles for the samples deposited in vacuum and O2 at different substrate temperatures look similar, except for a slight thickness variation.