Photoluminescence dynamics of amorphous Si/SiO2 quantum wells

We have studied photoluminescence (PL) spectrum and dynamics of amorphous silicon (a-Si) based quantum wells at low temperatures. In a-Si/SiO2 quantum-well samples with thin a-Si layers, the PL spectra appear in the visible spectral region. With a decrease of the a-Si well thickness, the PL peak energy shifts to higher energy and the PL lifetime becomes shorter. The well-thickness and temperature dependence of the PL lifetime show that the nonradiative recombination of carriers occurs at the a-Si/SiO2 interface and the lifetime is determined by the energy relaxation process in the a-Si well and the carrier diffusion to the interface. The quantum confinement and localization of carriers in a-Si/SiO2 quantum-well structures will be discussed.