Order and disorder and their influences on optical absorption of glasses in the gap region
- Faculty of Civil Engineering, Slovak University of Technology, Radlinského 11, 81005 Bratislava (Slovakia)
- Faculty of Materials and Technology, Slovak University of Technology, J.Bottu 25, 91724 Trnava (Slovakia)
The exponential increase of the absorption coefficient near the absorption edge is usually explained by existence of the density-of-states tails. Among the quoted theoretical models which are widely used to explain the manifestations of the Urbach rule in semiconductors, are the Sumi–Toyozava and the Dow–Redfield models and ab initio (from beginning) theory. Our barrier-cluster-heating model assumes the different creating mechanism of exponential tails. The energy by optical transition is provided to electrons except from photons also from vibration of microregion. It deals about the replenishment of absented photons energy, which is smaller as gap width. Absented energy needed for the transition by light absorption is accumulated in certain microregions of material in the form of vibrational energy. At absorption sufficiently big package of accumulated energy can be used. Energy of emptied microarea is filled by phonons from surrounding of microarea (as result of temperature status of surrounding), resp. phonons of optical background which are created in given microarea at non radiative recombination of carriers. In this work simplified process at derivating of Urbach rule is listed.
- OSTI ID:
- 22608486
- Journal Information:
- AIP Conference Proceedings, Vol. 1752, Issue 1; Conference: THERMOPHYSICS 2016: 21. international meeting on thermophysics, Terchova (Slovakia), 12-14 Oct 2016; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
- Country of Publication:
- United States
- Language:
- English
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