A method is proposed to analyze the optical absorption and electrical conductivity of non-crystalline materials having a high concentration of localized mid-gap states. The method is applied to dual ion beam deposited silicon nitride films containing various N contents. In this method, the optical absorption spectrum is fitted by using hypothetical functions of the density of states (DOS). The contribution from electron transitions between localized states is taken into account. The DOS at the Fermi level (Ef) was found to be very high (1019-1020eV-1cm-3), so that hopping of charge carriers around Efdominates the transport properties. Combined with the data of electrical conductivity, the hopping distance and the spread of the electron wave function of the charge carriers at Efare calculated. Furthermore, the temperature dependence of the mobility of the charge carriers at Efis also deduced.
|Number of pages||6|
|Journal||Applied Physics A: Materials Science and Processing|
|Publication status||Published - 27 Oct 2003|
ASJC Scopus subject areas
- Materials Science(all)