Luminescence properties of Zn2SiO4:Mn2+ thin-films by a sol-gel process

Thin film of Zn2SiO4:Mn2+ has been deposited on SiO2 buffered Si (SiO2/Si) wafers by the sol-gel process by means of a spin coating. Structural details of these films have been examined with X-ray diffraction (XRD) profiles and found to be rhombohedral structures. AFM images of the films have revealed that the structure has nano-meter size particles of about 130-160 mn in diameter and surface roughness RMS of 15 nm. FTIR profiles of these films have confirmed that OH content decreases with increasing annealing temperature and thereby enhancing the emission intensity. The OH content has disappeared when the films were annealed at 900 degreesC and above. Thin films of Zn2SiO4 containing a 5 mol% Mn2+ annealed at 1000 degreesC for about 10 min have shown a bright green luminescent color at 525 mn [T-4(1)((4)G) --> (6)A(1)(S-6) transition]. Luminescence spectra beyond 5 mol% of Mn2+ :Zn2SiO4 have shown a decreasing trend in their green emission behavior due to a cross-relaxation process. A double exponential fitting analysis has been employed to obtain the lifetime of this green emission, the average lifetime was found to be 8.233 ins. Such an encouraging luminescence performance from these thin films strengthens our proposal in developing them as flat panel luminescent systems. (C) 2003 Elsevier Science B.V. All rights reserved.