硅烷对纳米硅薄膜微结构和光学性能的影响

Influence of silane content on micro-structure and optical property of nc-Si:H films

通过改变反应气体中硅烷体积分数,采用直流偏压辅助等离子体化学气相沉积法在玻璃衬底上沉积本征氢化纳米硅薄膜.使用拉曼光谱仪、原子力学显微镜和紫外可见光透射仪对薄膜进行测试,研究不同硅烷体积分数对薄膜微结构和光学性能的影响.结果表明:当硅烷体积分数增加,晶粒尺寸增加,而晶态含量却随之下降.晶态含量的降低,使拉曼光谱中谱峰的强度降低,峰位发生蓝移,薄膜有序性随之降低;而且薄膜的光学禁带宽度随硅烷体积分数的增加而增加.当硅烷体积分数为1.3%时,沉积本征氢化纳米硅薄膜,薄膜中晶粒分布均匀,其生长存在取向性.此时晶态含量约为50%,晶粒尺寸约为2.6 nm;薄膜具有较大的光学禁带宽度,为1.702 eV,以及较高的电导率.

The intrinsic hydrogenated nano-crystalline silicon films of varied silane volume fraction have been deposited on the corning 7059 glass substrate by plasma enhanced chemical vapor deposition assisted with direct current bias.By Raman spectrometer,atomic force microscope and ultraviolet-visible transmission spectrometer the effects of the different silane volume fraction on the micro-structure and opticalproperty of films have been studied.The results show that when silane volume fraction increases,the crystalline size increases,whereas the crystal content decreases.The decrease of crystal content is the main cause for the decrease of the Raman peak intensity,the blue shift of peak position as well as the weakness of ordering character.The optical band-gap is in direct ratio to silane volume fraction.When silane volume fraction is equal to 1.3%,the films are deposited.Even nano-size crystals distribute regularlyand their deposition is in ordered orientation.The crystalline size and crystal content of these samples are nearly 2.6 nm and 50%.The film exhibits a large optical band-gap of 1.702 eV and a relatively high conductivity.