纳米Si/SiO2多层膜的结构表征及发光特性

采用等离子体化学气相沉积系统生长非晶硅薄膜并用原位等离子体氧化的方法制备出具有不同子层厚度的非晶Si/SiO₂多层膜,然后利用限制性晶化原理使非晶硅层晶化生成纳米硅。利用Raman、TEM等手段对薄膜结构进行了系统表征,在室温下观测到了光致发光信号,其发光峰峰位在750nm附近。进而在样品上下表面蒸镀电极,构建了电致发光原型器件并观测到了室温下的电致发光谱,开启电压约为6V,有两个明显的发光带,分别位于在650nm和520nm处。初步探讨了纳米硅及纳米硅/二氧化硅界面态对发光特性的影响。

The Structural and Optical Properties of nc-Si/SiO2 Multilayers

Amorphous-Si:H/SiO₂ multilayers with various sub-layer thicknesses were layer-by-layer deposited and in situ plasma oxidized in a plasma-enhanced chemical vapor deposition system. Nano-crystalline Si can be formed in the initial a-Si sub-layers based on the constrained crystallization principal. Raman scattering and TEM measurements were used to characterize the structure of multilayers during the formation of nc-Si/SiO₂ multilayers. It was found that the annealing temperature and the a-Si:H sub-layer thickness influence on the crystallization process obviously. Photoluminescence was observed at room temperature and the PL peak position is about 750 nm. Light-emitting Diode with MOS (Metal-Oxide-Semiconductor) structure was designed and fabricated by evaporating Al electrodes on both the upper and the bottom surface of the sample. Electroluminescence at room temperature was also observed by the naked eye with the turn-on voltage of 6 V. The EL spectra contain two luminescence bands located at 520 nm and 650 nm, respectively. The influence of nc-Si and interface of nc-Si and SiO₂ on the luminescent character of the device was briefly discussed.