Electron-phonon renormalization of electronic band gaps of semiconductors: Isotopically enriched silicon

摘要

Photoluminescence and wavelength-modulated transmission spectra displaying phonon-assisted indirect ex-citonic transitions in isotopically enriched ~(28)Si, ~(29)Si, ~(30)Si, as well as in natural Si, have yielded the isotopic mass (M) dependence of the indirect excitonic gap (E_(gx)) and the relevant phonon frequencies. Interpreting these measurements on the basis of a phenomenological theory for (partial deriv E_(gx)/partial deriv M), we deduce E_(gx)(M=∞) = (1213.8 ± 1.2) meV, the purely electronic value in the absence of electron-phonon interaction and volume changes associated with anharmonicity.