Suppression of UV photoluminescence in sandwich-structured composite films

Department of Physics, Block 12, Faculty of Science, National University of Singapore 2 Science Drive 3, Singapore 117542

Corresponding author: phyongpp@nus.edu.sg

Received: 22 May 2002
Accepted: 2 August 2002

Abstract

Thin films of composite silicon/carbon () were prepared by pulsed-laser ablation alternately on and materials on a rotary target, followed by vacuum deposition of the ablated materials on an ultra-clean glass substrate. The film structure consisted of alternate nanolayers of nanocrystals and amorphous , with a fairly sharp demarcation boundary between adjacent layers forming well-defined sandwich structures. At room temperature, this composite nanolayered structure was found to yield much lower photoluminescent (PL) emission in the ultra violet region (300–390) in comparison with that obtained for pure or for thin films (see Zhu Y., Wang H. and Ong P. P. J. Phys. D, 33 (2000) 1965, and Zhu Y. and Ong P. P. J. Phys. Condens. Matter, 13 (2001) L1). The suppression mechanism of the UV PL emission appeared to occur in the interfacial surfaces between adjacent crystalline and amorphous layers. It provides a possible way to selectively filter out the usually undesirable UV component of the PL emission from the silicon nanoparticles.