Visible photoluminescence and quantum confinement effects in amorphous Si/SiO2 multilayer structures

Abstract We have prepared amorphous silicon (a-Si)-based multilayer structures by an electron beam deposition technique and studied their luminescence properties. The structure of a-Si/SiO2 multilayers was studied by transmission electron microscopy and X-ray diffraction analysis. With a decrease of the a-Si well thickness, the PL peak energy shifts to higher energy. The temperature dependence of the PL spectrum suggests that the blueshift of the mobility edge occurs and the size-dependent visible luminescence is ascribed to radiative recombination of carriers localized in the shallow tail state. The quantum confinement effects of localized carriers will be discussed.