EFFICIENT VISIBLE PHOTOLUMINESCENCE FROM POROUS SILICON

It is shown that UV-excited porous Si (PS) exhibits an efficient visible photoluminescence (PL) at room temperature. The PS layers were formed by anodization of p-type and n-type single-crystal Si wafers in aqueous HF solutions. The peak wavelength of PL spectra depends on the anodization parameters including the resistivity and the conduction type of Si substrates. The PL spectra can be tuned to a higher energy side by either adjustment of the anodizing conditions or chemical etching after anodization. These remarkable results can be interpreted as a result of quantum size effects in PS.