Ion‐beam synthesis and thermal behaviour of luminescent Zn₂SiO₄ nanoparticles in silica glasses and films

Abstract

In the present study, the temperature-dependent photoluminescence (PL) spectra of Zn 2 SiO 4 nano-crystalline phases formed in glassy and thin-film SiO 2 matrices by means of ion implantation and annealing are studied. Pure willemite ceramics were used as a reference. The green and yellow light emission observed is associated with point defects inside aand b-Zn 2 SiO 4 nanoparticles. Different PL excitation mechanisms were distinguished for implanted silica. The electronic states of point defects are localised to dimensions much smaller than the nanocrystal size, so the PL band positions are similar to those of bulk material. Conversely, the vibrational states are extended and therefore subjected to the effects of confinement, surface defects and disorder of the host matrix. Hence, the PL intensity quenching (different laws for a-phase and b-phase) and line broadening shed light to the PL emission mechanism and reveal the influence of the amorphous silica matrix. The results obtained may be used to tailor the optical properties of the nanocomposite over a wide temperature range.

Doping effect by SiO2 on optical properties of ZnO Thin Films Prepared by pulsed laser depositions (PLD) technique

“…Annealing lead to decreased levels of localized near valence band (decrease tails in the optical energy gap) as a result of crystallinety enhancement cause to increase the optical band gap . This results agree with references [13][14][15][16][17]. -Absorption increases by increasing doping rates.…”