THE DENSITY OF GAP STATES IN A-SIH

The density of states (DOS) near the Fermi level is studied for hydrog enated amorphous silicon (a-Si: H) thin films using the space charge l imited current technique (SCLC). Experiments using films of different thicknesses show that surface states significantly contribute to the D OS. Investigations of both front and back contacts indicate that the f irst deposited layers imply DOS higher than the rest of the film. The study also shows that the film characteristics are dominated by the,to p electrode.