Energy dependence of electron-capture cross section of gap states inn-typea-Si:H

Isothermal capacitance transient spectroscopy has been employed for the measurement of the capture cross section of continuously distributed trap levels in $a$-Si:H, and the energy dependence of the electron-capture cross section of gap states has been determined for the first time. Experimental results indicate that an electron-capture cross section of a localized level decreases exponentially with an energy depth measured from the mobility edge of the conduction band, suggesting that the multiphonon emission predominates in the electron-capture process at the deep gap states in $a$-Si:H.