氢化纳米硅薄膜的光声光谱研究

PHOTOACOUSTIC SPECTRA STUDIES OF HYDROGENATED NANOCRYSTALLINE SILICON FILMS

分析了纳米硅薄膜材料从可见光到近红外范围的光声光谱，并与微晶硅和非晶硅材料进行了对比．纳米硅的光吸收系数比后两者都高（特别是在１．４～１．９ｅＶ之间，高出近一个数量级），其原因是纳米硅薄膜中大量晶粒对光子的散射、晶粒界面缺陷的吸收及载流子吸收的影响，此外，纳米硅光声谱中Ｕｒｂａｃｈ边宽且缓，反映出这种材料很高的无序程度．

Photoacoustic (PA) spectra of hydrogenated nanocrystalline silicon Zhu Xiaotian is a visiting scholar from the Dept. of Math. and Mech. China University of Mining and Technology, Xuzhou (nc-Si:H), hydrogenated microcrystalline silicon (μc-Si:H) and hydrogenated amorphous silicon (a-Si:H) films have been presented and discussed. The optical absorption coefficient of nc-Si:H is much greater than those of the other two materials, especially at the region of the incident photon energy between 1 .4eV and 1 .9eV,the former exceeds both of the others by one order of magnitude. Three reasons may mainly be considered: there are great photon scattering of grains, the extra absorption induced by the defects at grain boundaries, and the absorption of carriers in nc-Si:H. Besides, the Urbach edges of nc-Si:H are wide and gradual, which indicates the high disorder of nc-Si:H.