Electron confinement and optical enhancement in Si/SiO2 superlattices - art. no. 195330

We have performed first-principles calculations of Si/SiO2 superlattices in order to examine their electronic states, confinement, and optical transit ions, using linearized-augmented-plane-wave techniques and density-function al theory. Two atomic models having fairly simple interface structure are c onsidered. They differ in the way dangling bonds at interfaces are satisfie d. The real and imaginary parts of the dielectric function are calculated a t the Fermi-golden-rule level and used to estimate the absorption coefficie nts. Confinement is demonstrated by the dispersionless character of the ele ctronic band structures in the growth direction. Optical enhancement is sho wn to exist by comparing the direct and indirect transitions in the band st ructures with the related transitions in bulk Si. The role played by the in terface on the optical properties is assessed by comparing the absorption c oefficients from the two models.