Effects of the Fabrication Processes of NC-Si:H Films on Their Mechanical Properties

Studies of nanoindentation were performed on nc-Si:H films to evaluate the effects of the fabrication processes on their mechani-cal properties. It is observed that with the decrease of the SiH4 contents, the grain size of the films increases gradually, and as does the crystalline volume fraction. The smaller the grains become, the more homogeneous the films, and the more even the hardness as well as the modulus will be. The hardness and the modulus will increase with the substrate’s temperature rising. The hardness and the modulus of the nc-Si:H films on the Si substrate prove to be higher than those on the glass substrate given the same technology parameters. How-ever, the films on the glass substrate appear to be more homogeneous.     

掺铒纳米硅的选择激发光荧光研究

通过选择激发光荧光技术研究了生长在SiO2中的掺铒纳米硅（nc—Si：Er）的光学性质。当激发光光子能量高于1．519eV时,nc—Si：Er的室温光荧光谱上能够看到两个清晰的发光峰,一个来自nc—Si,峰值位置在1．39eV,标记为Enc-Si;另一个发光来自nc—Si附近的Er离子,峰值位置在0．81eV,标记为EEr,当激发光的光子能量为1．42eV时,尽管该能量高于Enc-Si和EEr的峰值能量,在nc—Si：Er的室温光荧光谱上既看不到Enc-Si的发光蜂,也看不到EEr的发光峰。研究发现,当激发光光子能量与Er离子的一些激发态能量共振时,来自Er离子的荧光峰（EEr）出现共振增强现象,同时来自nc—Si的荧光峰峰值强度则有一定程度的降低。结果表明,nc—Si：Er中的共振增强现象是由于共振激发增强了载流子从nc—Si向临近的Er离子传输过程。