非晶SiCxOy薄膜的可调强光发射机制

摘要

采用甚高频等离子体增强化学气相沉积技术,以SiH4、CH4和O2作为反应气源,通过调控O2流量在250 ℃下制备强光发射的非晶SiCxOy薄膜.利用光致发光光谱、荧光瞬态谱、Raman光谱、X射线光电子能谱及红外吸收谱对薄膜的光学性质和微结构进行表征与分析,进而讨论其可调可见光发射机制.实验结果表明,SiCxOy薄膜发光性质与薄膜中的氧组分密切相关.随着薄膜中氧组分的增加,其发光峰位由橙红光逐渐向蓝光移动,肉眼可见强的可见光发射.荧光瞬态谱分析表明,薄膜的荧光寿命在纳秒范围.结合X射线光电子能谱和红外吸收谱对薄膜的相结构和化学键合结构进行分析,结果表明薄膜的主要相结构和发光中心随O2流量的变化是其可调光发射的主要原因.%The strong luminescent amorphous silicon oxycarbide (a-SiCxOy) films with different O content were prepared by very high frequency plasma enhanced chemical vapor deposition (VHF-PECVD) at 250 ℃ by using the gas mixture of SiH4, CH4 and O2 as the precursor.The effect of O content on the luminescent properties and structure of SiCxOy thin films was investigated.It is found that the increase of O content results in remarkable photoluminescence (PL) with orange-red to blue shifting emission, which can be clearly observed with the naked eyes in a bright room.The PL of the a-SiCxOy film is suggested from the nanoseconds recombination lifetime.The microstructure and the chemical compositions of the films were further investigated by Raman spectra, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared absorption (FTIR) spectroscopy, respectively.Combining with the PL results and the analysis of the chemical bonds and microstructure present in the films, the main phase structure of the films and the change of the luminescent center with the O2 flow rate are the main reasons for the tunable light emission.