Visible electroluminescence in hydrogenated amorphous silicon oxynitride

The mechanism of electroluminescence in hydrogenated amorphous silicon oxyn itride was investigated. The luminescence can be observed only in the sampl es with high nitrogen content and annealed at high temperatures. It depends on the direction of the applied electric field, and its peak photon energy decreases from 2.3 to 1.8 eV as the nitrogen content increases. From the m easurements of conduction current and Fourier transform infrared absorption spectroscopy, it was found that the electrical conduction in the electric field region where the luminescence was observed is governed by the Poole-F renkel process at the defect centers induced by the high temperature anneal ing. The electroluminescence is considered to be caused by electronic trans ition between the band-tail states, at least one of which is related to N o r Si-N bonds. (C) 2001 American Institute of Physics.