Dependence of PL(photo-luminescence) of PS(porous silicon) and its structural change on PS's fabrication process were studied. And the electrical properties of PS and PL shift by bias stress were studied.
PL peak shifted to high energy when the time of anodization and the time of chemical etching were increased. And PL peak showed blue shift as anodization current density increased. Dry oxidation at a few torr atomospheric pressure and temperature above 700℃ could shift PL peak to high energy and intensify PL. These facts are results of inhancement of quantum confinement and reduction of PS(porous silicon)'s micro structure size.
Conductance of PS decayed as stretched exponential form. The decay process is irreversible. This is due to oxidation of wall surface of PS, surface defect creation and charge trapping by surface defect. I-V curve of saturated PS showed a novel feature. This can be explained when quantum box model is adopted, also.
All thesee facts confirm quantum confinement model as the origin of the PL of PS.