Efficient solar-to-chemical conversion by one chip of n-type silicon with surface asymmetry

The surface band energy of an n-type silicon (n-Si) chip in aqueous solutio n has been modulated by formation of silicon-halogen termination bonds on a limited area of the Si surface. Such surface asymmetry produces efficient solar-to-chemical conversion owing to the presence of band bending within t he n-Si chip in a photostationary state, leading to efficient electron-hole separation, in contrast to homogeneous semiconductor surfaces. The princip le can be applied to minute photochemical energy conversion systems made of nanometer-sized semiconductor particles, organic thin films, and membranes . (C) 1998 The Electrochemical Society. S1099-0062(98)02-010-0. All rights reserved.