MEASUREMENT OF THE DENSITY OF THE GAP STATES IN a-Si:H BY THE NORMALIZATION OF PHOTOCONDUCTIVITY
光电导归一化法测量α-Si:H隙态密度

The spectra of the optical absorption conficient in the low absorption region are obtained by using a normalization procedure for the photoconductivity spectra. The results are explained in terms of optieal transitions of electrons from loealized states in exponential valence-band tail and in danglihg bond states. 1.0 eV below the conduction-band edge to extended states above the conduction-band edge. Then the density of the gap states below the Fermi energy EF is abtained. From the investigation of recombination kinetics, the average density of the gap states in the range of (EFn-EF) is obtained. Then the density of the gap states above the Fermi energy EF is obtained. It indicates that the width of the conduction-band tail is narrower than that of valence-band tail.