There are many preparation methods of porous silicon(PS), such as electrochemical
etching(ECE), photochemical etching, chemical etching and so on. ECE, also known as anodic etching,
is more common among these methods. A lot of holes are given priority to be etched on the surface of
silicon. The top and vertical aspects of the holes are easily etched while horizontal aspects wall of the
holes are quiet different, and then tree-like or sponge-like porous structure is formed. In this paper, we
obtained porous structure on the surface of silicon using lithography and dry etching method. The
diameter of the hole was 2μm or 6μm. The etching depth of the samples was about 70nm, 140nm and
260nm. Photoluminescence (PL) phenomenon was observed by using light of 270nm, 280nm, 330nm,
455nm and 460nm wavelength to excite the samples. The results showed that PL intensity was the best
when excitation wavelength was 270nm or 280nm, compared with 330nm, 455nm and 460nm. From
PL analysis of all samples, It exists three emission peaks about at 372nm, 425nm and 473nm. When the
diameter of the PS was the same, it was found that PS with etching depth at 140nm was more efficient.
It means that PL intensity of the was better than other samples when the etching depth was 140nm.
Likewise, samples of which the diameter was 2μm has much better PL than that of the other samples.