Growth and optical properties of nanocrystalline Gd 3Ga 5O 12:Ln [formula omitted] powders and thin films via Pechini sol–gel process

Abstract

Rare earth (Eu 3+, Tb 3+, Er 3+)-doped gadolinium gallium garnet (Gd 3Ga 5O 12, GGG) nanocrystalline powder and thin film phosphors were prepared by the Pechini sol–gel process. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) as well as photoluminescence (PL) spectra were used to characterize the resulting powder and film samples. Both the powders and the coatings crystallized completely at 800 °C. The dopant rare earth ions show their characteristic emissions in Gd 3Ga 5O 12 phosphors, i.e., 5D 0– 7F J ( J = 1 , 2 , 3 , 4 ) transitions for Eu 3+, 5D 4– 7F J ( J = 3 , 4 , 5 , 6 ) transitions for Tb 3+ and ( 2H 11/2– 4I 15/2, 4S 3/2– 4I 15/2) transitions for Er 3+, respectively. In addition, the near infrared emission spectra (NIR) and the near infrared to visible upconversion (anti-Stokes) luminescence of Er 3+ were also observed in the Er 3+-doped Gd 3Ga 5O 12 samples. Possible mechanism responsible for the upconversion luminescence of Er 3+ was proposed.