非晶硅中的缺陷态光吸收谱

Defect Optical Absorption in a-Si:H

非晶硅薄膜的光学及电学性质与共电子局域态分布紧密相关。为了改进非晶硅薄膜器件的性质,如太阳能电池、薄膜晶体管等,需要低局域态密度的材料,因而测量并了解局域态的性质十分重要。局域态包括带尾态、缺陷态及亚稳缺陷态。本文着重讨论缺陷态及亚稳缺陷态。

An extra band of change in optical absorption was observed by means of Infrared Stimulated Current method (IRSC) for either native or light- induced metastable defects in a-Si:H.Both the spectral distribution of the extra absorption and the relaxation of the light-induced metastable states are different from those of native defects. The photo-induced absorption spectra △α/α of a-Si:H samples can be obtained by measuring the primary and the second harmonic of Photothermal Deflection Spectroscopy(PDS) signal. From the △α/α we can indicate the defect state energy levels, thus studying the new gap states caused by doping.