Abstract: Scanning tunneling microscopy(STM)combined with fast Fourier transforms(FFT)and data simulation methods were used to examine the surface morphology and microstructure of porous silicon(PS)formed by electrochemical anodic oxidation.The relation betweenmicrostructure and characteristics of electrochemistry and photoluminescence was studied.The results showed that with the increase of etching current density the micropores expanded in the depth direction and the thickness of porous layer enhanced and the remaining Sicolumns became thiner. Corresponding to the change of the microstructure the luminescentintensity increased and the peak shifted toward shorter wavelength with increasing currentdensity, In contrast to crystal Si the flatband potential of PS was more negative and the cur-rent densities in cathodic and anodic region were increased simultaneously.

Key words: scanning tunneling microscope, porous silicon, microstructureTo whom correspondence should be addressed.