Pore formation on n-InP

The present work deals with localized dissolution processes of n-type InP(1 00). pore growth call be electrochemically initiated on the n-type material in the dark in HCl HBr and HF solutions and leads after extended polarizat ion to the formation of a porous InP structure. The porous structures were characterized by SEM, AES, and PL measurements. The pore morphology depends strongly on the electrochemical conditions and the type of halogen acid pr esent in the electrolyte. AES depth profiles show that the composition of t he porous layer is strongly affected by the electrolyte. For all electrolyt es depletion of In was observed; this effect is the strongest for HBr and t he weakest for IIE Uptake of electrolyte anions is the highest for HBr and lowest for HE From scratch experiments it is clt al that the pole initiatio n process is strongly influenced by surface defects. The morphology of the dissolution process also strongly depends on illumination as assessed by an experiment using a laser beam for a local surface illumination. At high il lumination intensity, electropolishing instead of port: formation takes pla ce. The finest pore structure was obtained in the dark. Structures for mcd in HF show visible photoluminescence in the yellow to red range of the spec trum, whereas fur HCl and HBr treated samples no significant visible PL was obtained.