Laser structuring of luminescent porous silicon during etching

A new approach to the problem of preparation of laterally structured lumine scent porous silicon is proposed. The effect is based on the photosensitivi ty of chemical etching of silicon. Contrary to the other technique recently reported where the porous layer was modified with light assisted chemical dissolution, a one stage anodisation-free process is used. Any desired late ral structure can be produced, depending on the illumination pattern, which is defined by optical imaging. A 2D micro-array was prepared as an example of this fast mask-free technology with an accuracy of 5 mu m. Samples have a broadband visible photoluminescence centred at 680 nm when illuminated w ith UV or blue light. The results are analysed to determine the possible ac hievable accuracy of the technique and to improve our understanding of the mechanism of light assisted etching.