A method for the fabrication of n-type porous silicon (n-PS) is developed. The Hall effect is applied in the fabrication process. The majority carriers in n-type Si (electrons) are swept down by the Lorentz force. Enough holes continuously appear on the surface layer to participate in chemical reaction during the etching process. Illumination sources are not necessary in this method. Therefore, no illumination limit has to be concerned in the formation of deep PS layer. The morphology, porosity, and photoluminescence of the n-PS prepared by the proposed method are investigated. Strong visible photoluminescence emissions are demonstrated on n-PS at about 650 nm. (c) 2006 American Institute of Physics.
