Structure, morphology, and luminescent behavior of RE3+-doped GdVO4 thin films

Abstract

This report focuses on fabrication, characterization, and fundamental optical properties of Eu3+- and Sm3+-doped GdVO4 luminescent thin films. Films were uniformly grown on three different substrates: single crystal sapphire (0001), thermally grown silicon oxide (Si/SiO2 ~ 500 nm) on silicon and fused quartz using pulsed laser deposition technique. Thin films’ structure, morphology, and photoluminescent properties were investigated by X-ray diffraction, atomic force and scanning electron microscopy, diffuse reflectance and photoluminescence spectroscopy. Thin films’ structure characterized by X-ray diffraction showed that for all substrates highly crystalline, zircon-type pure phase films were formed. Films’ thickness and internal morphology were determined by cross-sectional scanning electron microscopy showing completely dense, pore-free film with an average thickness of ~ 390 nm. Atomic force microscopy revealed that the average crystallite size of both Eu3+- and Sm3+-doped GdVO4 thin films deposited on fused quartz is higher as compared to the single crystal sapphire (0001) and thermally grown silicon oxide (Si/SiO2 ~ 500 nm) and that the surface roughness increases with the increase in the grain size. Energy band gap values, estimated from diffuse reflectance spectra were 3.57 and 3.53 eV for Eu3+- and Sm3+-doped GdVO4 thin films, respectively. Photoluminescent properties were investigated in detail in both steady state and lifetime domain. The emission spectra show clear orange–red emission in the Sm3+-doped GdVO4 thin films and red emission in Eu3+-doped ones.