Prakash G V, Daldosso N, Degoli E, Iacona F, Cazzanelli M, Gaburro Z, Pucker G, Dalba P, Rocca F, Ceretta Moreira E, Franzò G, Pacifici D, Priolo F, Arcangeli C, Filonov A B, Ossicini S, Pavesi L
INFM, Dipartimento di Fisica, Università di Trento, via Sommarive 14, 38050, Povo, Trento, Italy.
J Nanosci Nanotechnol. 2001 Jun;1(2):159-68. doi: 10.1166/jnn.2001.024.
Silicon nanocrystals (Si-nc) embedded in SiO2 matrix have been prepared by high temperature thermal annealing (1000-1250 degrees C) of substoichiometric SiOx films deposited by plasma-enhanced chemical vapor deposition (PECVD). Different techniques have been used to examine the optical and structural properties of Si-nc. Transmission electron microscopy analysis shows the formation of nanocrystals whose sizes are dependent on annealing conditions and deposition parameters. The spectral positions of room temperature photoluminescence are systematically blue shifted with reduction in the size of Si-nc obtained by decreasing the annealing temperature or the Si content during the PECVD deposition. A similar trend has been found in optical absorption measurements. X-ray absorption fine structure measurements indicate the presence of an intermediate region between the Si-nc and the SiO2 matrix that participates in the light emission process. Theoretical observations reported here support these findings. All these efforts allow us to study the link between dimensionality, optical properties, and the local environment of Si-nc and the surrounding SiO2 matrix.
通过对等离子体增强化学气相沉积（PECVD）法沉积的亚化学计量比SiO x 薄膜进行高温热退火（1000 - 1250℃），制备了嵌入SiO₂ 基质中的硅纳米晶体（Si-nc）。已采用不同技术来研究Si-nc的光学和结构性质。透射电子显微镜分析表明形成了纳米晶体，其尺寸取决于退火条件和沉积参数。通过降低退火温度或PECVD沉积过程中的硅含量获得的Si-nc尺寸减小，室温光致发光的光谱位置会系统性地蓝移。在光吸收测量中也发现了类似趋势。X射线吸收精细结构测量表明，在Si-nc和参与发光过程的SiO₂ 基质之间存在一个中间区域。此处报道的理论观察结果支持了这些发现。所有这些工作使我们能够研究Si-nc的维度、光学性质以及其与周围SiO₂ 基质的局部环境之间的联系。
