Preparation and photoluminescence characteristics of various-sized carbon clusters embedded in xAL_2O_3-xP_2O_5-100SiO_2 gel-glasses

摘要

The discovery of visible photoluminescence (PL) from porous silicon (PS) [1] has triggered great interest in the study of Si-based light-emitting materials. In order to clarify the origins of the luminescence and exploit the potential for applications in optoelectronics, Si and Ge nanocystals embedded in a SiO_2 matrix have been pre-pared by various methods, and room-temperature PL has been observed in the visible spectral region [2-10]. The sizes of the crystallites are of the order of several nanometers. The quantum confinement (QC) model is one of those used to explain the optical luminescence properties of these materials [11, 12]. Another explanation for the visible PL has been given by Kanemitsu and others, which involves interfacial states between the semiconductor crystallites and SiO_2 matrix [13-15]. However, little attention has been paid to the PL properties of microstructures made of carbon. Recently C-SiO_2 composite films have been prepared by a rf co-sputtering technique, and a strong PL centered between 550 nm and 680 nm was observed [16-17].