Photoconductive properties of nanometer-sized Si dot multilayers

Nanometer-sized Si dot multilayers have been prepared by repeating a sequen ce of low-pressure chemical vapor deposition for dot formation and thermal oxidation for dot isolation. For the multilayer with Si dots in the range o f 3-5 nm, the onset of photoconductivity is observable at a photon energy o f 2 eV, corresponding to the optical absorption edge of the Si dots. This r esult indicates that the nanometer-sized Si dot multilayers are promising a s photoconductors that work at various wavelengths because the optical band gap can be varied by controlling the dot size. (C) 2001 American Institute of Physics.