Stable electrochemically passivated Si surfaces by ultra thin benzene type layers

Ultra thin organic layers of benzene type molecules are able to passivate Si surfaces. The organic layers were electrochemically deposited on Si surfaces from aqueous solution of diazonium compounds and show a blocking of the charge transfer from Si into the electrolyte after the deposition process. Electron microscopic images reveal a compact and homogeneous organic layer of 4 bromobenzene on the Si. The surface recombination increases only slightly with respect to a well H passivated Si surface, so that the interface state density is about 1011 cm2 or slightly below. Organic layer modified Si surfaces are much longer stable in ambient air than the H terminated surface as observed by a slower decay of the integrated photoluminescence intensity with time. Thermal desorption measurements show that the organic layer is stable up to about 200