Effects of final-state interactions on modulation spectra of semiconductors☆

摘要: Abstract Theories of modulation spectra are critically reviewed with particular attention paid to the effects final-state interactions (exciton effects). These lead formation bound exciton states and also strongly correlate motions unbound electrons holes, resulting in optical absorption that diner significantly from square-root shapes predicted by one-electron, independent-particle model. The depend sensitively on Coulombic nature electron-hole interaction cannot be reproduced a short-ranged contact-exciton model interaction. well-known differences between one-electron theory Elliott accentuated differentiation, leading (in most cases) enormous two theories. Experimental data generally confirm predictions lend support claim exert dominant influence sizes spectra. For example, virtually all structures semiconductors due lie at energies displaced critical points interband densities states. very spectroscopy, which measures small large numbers, puts severe demands any quantitative lineshapes. To date, no has met those sense been able accurately describe measured lineshape without resorting use one or more adjustable parameters. A simple, qualitative description electroabsorption is presented, it demonstrated these manifest themselves observed excitonic valid limit weak broadening, situation rarely achieved experimentally. reduce importance broadening processes, especially prominent zero fields, both fields should uniform.