A NOVEL NANOPOROUS SILICON PREPARED USING ELECTROCHEMICAL DEPOSITION TECHNIQUE FOR LIGHT EMITTING DIODE APPLICATIONS

The electroluminescence (EL) studies on the aluminum-doped nanoporous silicon (NPSi:Al) have been conducted. Nanoporous silicon (NPSi) layers have been prepared by anodically etching the unpolished p-type Si[100] wafer with surface resistivity of 4–8 Ω cm-1 in hydrofluoric solution at 1:1 ratio of ethanol. Aluminum (Al) was doped on NPSi using cathodic electrodeposition composed of aluminum chloride (AlCl3) and ethanol electrolyte. A diode structure has been fabricated comprising a semi-transparent Au/NPSi:Al/p-Si/Al ohmic contact electrode showing rectification on a forward bias I–V curve. EL from NPSi and NPSi:Al/p-Si has also been observed using the diode structure. The NPSi:Al/p-Si device shows increasing EL quantum efficiency at about 30%, and blue-shift EL spectra are observed. Possible reasons for the enhancement will be discussed.