Blue and green electroluminescence from a porous silicon device

The fabrication and the characteristics of light-emitting porous silicon devices are presented. A nanoporous layer on n-substrate is formed under the influence of UV illumination during anodization. The wafer shows weak photoluminescence with a maximum at 640 nm. The porous layer is contacted by pads consisting of semitransparent gold. When voltage is applied, electroluminescence in the 560- to 480-nm range can be observed. The current-voltage characteristic is strongly rectifying. Light emission occurs under forward bias. A possible model for the shift of the electroluminescence toward higher energies is given.<
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