Macroporous silicon formation on n-Si in room-temperature fluorohydrogenate ionic liquid

This communication reports the formation of porous silicon (PS) by application of a positive potential on n-type silicon without illumination. PS films were formed in 1-ethyl-3-methylimidazolium oligofluorohydrogenate [EtMeIm(FH) 2.3 F] room-temperature ionic liquid, and the surface morphology strongly depended on the time and the applied potential. The results indicate that EtMeIm(FH) 2.3 F could be a nonaqueous solvent equivalent to hydrofluoric acid, allowing the formation of pores under anodic polarization.