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.