Nanostructured Si/SiO2 Quantum Wells

Abstract

The motivation for developing light-emitting devices on an indirect transition semicon - ductor such as silicon has been widely discussed for Si/SiO 2 nanostructures. In this chapter, we report on the fabrication of Si/SiO 2 quantum-confined amorphous nanostructured films and their optical properties. The Si/SiO 2 nanostructures comprising amorphous Si, SiO 2 , and Si/SiO 2 multilayers are grown using ultrahigh vacuum radio frequency magnetron sputter - ing. Optical absorption coefficients of the Si/SiO 2 nanostructures are evaluated with regard to tentative integrated Si thicknesses. Optical energy band gaps of the Si/SiO 2 multilayer films are in accordance with the effective mass theory and described as E 0 = 1.61 + 0.75d −2 eV at the Si layer-integrated thicknesses ranging from 0.5 to 6 nm. Quantum confinement effects in the Si/SiO 2 nanostructures are inferred from optical transmittance and reflectance spectra. The rapid-thermal-annealed Si/SiO 2 multilayer films demonstrate the intensified photoluminescence at ~1.45 eV due to the formation of nanocrystalline silicon. The tem perature dependence of the nanocrystalline luminescence intensity shows the nonmonoto - nous behavior which is interpreted invoking the Kapoor model.