Visible electroluminescence from stain-etched porous Si diodes

Visible electroluminescence (EL) from stain-etched porous silicon (PoSi) films is presented. The PoSi thin layers (/spl sim/200 nm) were obtained by stain-etching of B-doped 6-16 /spl Omega/-cm [100] crystalline Si in a HF:HNO/sub 3/:H/sub 2/O (1:3:5) solution. Indium tin oxide (ITO) films of /spl sim/2500 /spl Aring/ were used to form a Schottky contact. Visible EL was observed at room temperature from the diode under forward bias. EL onset bias as low as 3 mA/cm/sup 2/ was measured. The EL, with an emission peak at /spl sim/640 nm, is similar to the photoluminescence under UV excitation, indicating the same luminescent centers. This result demonstrates a promising and simple technique for the fabrication of PoSi-based light emitting diodes and flat panel display devices.<>