|Title:||Optical Gain and Co-Stimulated Emissions of Photons and Phonons in Indirect Bandgap Semiconductors||Authors:||Chen, M.J.
|Keywords:||indirect bandgap semiconductors;crystalline silicon;optical gain;co-stimulated emission of photons and phonons;phonon-assisted optical transition;laser oscillation;nanostructured PN junction diode||Issue Date:||2006||Publisher:||Taipei:National Taiwan University Dept Chem Engn||Journal Issue:||45||Start page/Pages:||6576-6588||Source:||Japanese Journal of Applied Physics||Abstract:||
A model calculation on optical gain and co-stimulated emission of photons and phonons in indirect bandgap semiconductors
such as silicon is presented. An analytical expression for optical gain via phonon-assisted optical transitions in indirect
bandgap semiconductors is presented. Population inversion can occur when the difference between the quasi-Fermi levels for
electrons and holes is greater than the photon energy. The rate equations and their steady state solutions for electron, photon,
and phonon involved in the phonon-assisted optical transitions are presented. It is shown that co-stimulated emissions of
photons and phonons will occur when the threshold condition for laser oscillation is satisfied. The magnitude of optical gain in
bulk crystalline silicon is calculated and shown to be smaller than the free carrier absorption at room temperature. However, it
is shown, for the first time, that the optical gain is greater than the free carrier absorption in bulk crystalline silicon at the
temperature below 23 K. Thus, the calculation predicts that the co-stimulated emissions of photons and phonons could take
place in bulk crystalline silicon at the low temperature.
|Appears in Collections:||材料科學與工程學系|
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