具有窄光致发光谱的纳米Si晶薄膜的激光烧蚀制备

The laser ablated deposition of Si nanocrystalline film with narrow photoluminescence peak

采用XeCl脉冲准分子激光器,在10Pa的Ar气环境下,烧蚀高阻单晶Si靶,分别在距靶3cm的玻璃和单晶Si衬底上制备了纳米Si薄膜.相应的Raman谱和x射线衍射谱均证实了薄膜中纳米Si晶粒的形成.扫描电子显微镜图像显示,所形成的薄膜呈均匀的纳米Si晶粒镶嵌结构.相应的光致发光峰位出现在599nm,峰值半高宽为56nm,与相同参数下以He气为缓冲气体的结果相比,具有较窄的光致发光谱,并显示出谱峰蓝移现象.

The single crystalline Si target with high resistivity was ablated by a XeCl excimer laser （laser fluence 4 J/cm^2 , repetition rate 1Hz）, and at the ambient pressure of 10 Pa of pure Ar gas, the nanocrystalline silicon film was deposited on a glass or single crystalline （111） Si substrate located at a distance of 3 cm from the Si target in 30 and 10 min, respectively. The Raman and x-ray diffraction spectra of the film deposited on the glass substrate indicate the film is nanocrystalline, which means that it is composed of Si nanoparticles. Scanning electron microscopy of the film on the Si substrate shows that the film has the mosaic structure of Si nano-crystallites of uniform size. The photoluminescence peak wavelength is 599 nm with full width at half maximum of 56 nm, which is blue-shifted and narrower than that obtained in He gas.