Abstract: The microstructure and morphology of photoluminescent porous silicon have beenstudied by using scanning tunneling microscope(STM).The changes of the sponge-likeporous structure observed on chemically etched silicon surface are quantitatively indicatedby the changes of the roughness parameters R_a,R_q,and R_y.The porous silicon formed bysimple chemcial etching,like the porous silicon produced anodically, can also emit visible luminescence at room temperature;and their emitting properties are closely related to theformation conditions.The results provide microstructure information for supporting the quantum coulinement effect as the luminescence mechanism.

Key words: scanning tunneling microscope, porous silicon, microstructure