A mask-free method of patterned porous silicon formation by a localized electrical field

A simple and mask-free method is proposed for the fabrication of p-type patterned porous silicon (PS) using a localized electric field. The electric field is applied by the patterned electrodes (anode and cathode) which are horizontally placed underneath the sample. No masking-layer and related photo-lithography process are needed in this method. Besides, no metal electrodes and hence no metal-pollution in electrolyte have to be concerned in the formation of PS. The morphology of the PS prepared by this method is investigated. Strong visible photoluminescence emissions in the selected areas of PS are demonstrated on PS at about 650 nm.