ELECTROLUMINESCENCE FROM AU NATIVE-OXIDE P-SI AND ITS CORRELATION TO THAT FROM AU POROUS SI

Visible electroluminescence (EL) has been observed from Au/native oxide/p-Si diodes and has been studied in comparison to the EL from Au/porous Si (PS) diodes. Both kinds of diode share similarities in voltage-current characteristic, EL spectra, and the bias dependence of EL peak intensity. However, Au/PS exhibits quite strong photoluminescence (PL) while Au/native oxide/p-Si does not show any measurable FL. The native oxide layer plays a key role in light emission of Au/native oxide/p-Si; when the oxide layer was removed away in HF, no EL can be observed. We discuss the EL mechanisms for both kinds of the light-emitting diode and suggest a physics model for their EL.