Determination of the density of localized states in fluorinated a-Si using deep level transient spectroscopy

Abstract

The density of localized states distribution in fluorinated a-Si (a-Si:F:H) was investigated using a digital deep level transient spectroscopy (DLTS) system. The DLTS spectra indicate a minimum in the density of states of about 1015 cm−3 eV−1, which is comparable to the value previously reported for a-Si:H using DLTS. Since field-effect measurements show that the density of localized states is much lower in a-Si:F:H than in a-Si:H, we can conclude that the density of surface states in (a-Si:F:H) is much smaller than in a-Si:H. This has important consequences in potential applications of amorphous silicon-based films.