Anomalous enhancement in radiation induced conductivity of hydrogenated amorphous silicon semiconductors

Sato, Shinichiro; Sai, Hitoshi*; Oshima, Takeshi; Imaizumi, Mitsuru*; Shimazaki, Kazunori*; Kondo, Michio*

Nuclear Instruments and Methods in Physics Research B, 286, p.29 - 34, 2012/09

https://doi.org/10.1016/j.nimb.2012.02.039

Electric conductivity variations of undoped hydrogenated amorphous silicon (a-Si:H) semiconductors induced by swift protons are investigated. The results show that the conductivity drastically increases at first and then decreases on further irradiation. The conductivity enhancement observed only in the low fluence regime lasts for a prolonged period of time when proton irradiation stops in this fluence regime. On the other hand, the photosensitivity has a minimum value around the conductivity peak. This fact indicates that non-equilibrium carriers do not play a dominant role in the electric conduction in this fluence regime. It is found that the anomalous conductivity enhancement is dominated by donor center generation in the low fluence regime. At higher fluences the variation in electric conductivity becomes dominated by non-equilibrium carriers as the generated donor centers disappear. This is a general interpretation of radiation induced conductivity in semiconductors.