The Moss-Burstein effect, also known as the Burstein–Moss shift, is the phenomenon in which the apparent band gap of a semiconductor is increased as the absorption edge is pushed to higher energies as a result of some states close to the conduction band being populated. This is observed for a degenerate electron distribution such as that found in some degenerate semiconductors and is known as a Moss–Burstein shift.[1][2]
The effect occurs when the electron carrier concentration exceeds the conduction band edge density of states, which corresponds to degenerate doping in semiconductors. In nominally doped semiconductors, the Fermi level lies between the conduction and valence bands. For example, in n-doped semiconductor, as the doping concentration is increased, electrons populate states within the conduction band which pushes the Fermi level to higher energy. In the case of degenerate level of doping, the Fermi level lies inside the conduction band. The "apparent" band gap of a semiconductor can be measured using transmission/reflection spectroscopy. In the case of a degenerate semiconductor, an electron from the top of the valence band can only be excited into conduction band above the Fermi level (which now lies in conduction band) since all the states below the Fermi level are occupied states. Pauli's exclusion principle forbids excitation into these occupied states. Thus we observe an increase in the apparent band gap. Apparent band gap = Actual band gap + Moss-Burstein shift (as shown in the figure).
Negative Burstein shifts can also occur. These are due to band structure changes due to doping.[3]
Referencesedit
^Moss, T. S. (1954). "The Interpretation of the Properties of Indium Antimonide". Proceedings of the Physical Society. Section B. 67 (10): 775–782. Bibcode:1954PPSB...67..775M. doi:10.1088/0370-1301/67/10/306. ISSN 0370-1301.
^Burstein, Elias (1954-02-01). "Anomalous Optical Absorption Limit in InSb". Physical Review. 93 (3): 632–633. Bibcode:1954PhRv...93..632B. doi:10.1103/PhysRev.93.632.
^John.C Inkson (1984). "ch. 9.5, page 210". Many-Body Theory of Solids. Springer. ISBN0-306-41326-4.
Further readingedit
Marius Grundmann (2006). The Physics of Semiconductors. Springer Berlin Heidelberg New York: Springer. ISBN978-3-540-25370-9.
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moss, burstein, effect, moss, burstein, effect, also, known, burstein, moss, shift, phenomenon, which, apparent, band, semiconductor, increased, absorption, edge, pushed, higher, energies, result, some, states, close, conduction, band, being, populated, this, . The Moss Burstein effect also known as the Burstein Moss shift is the phenomenon in which the apparent band gap of a semiconductor is increased as the absorption edge is pushed to higher energies as a result of some states close to the conduction band being populated This is observed for a degenerate electron distribution such as that found in some degenerate semiconductors and is known as a Moss Burstein shift 1 2 The effect occurs when the electron carrier concentration exceeds the conduction band edge density of states which corresponds to degenerate doping in semiconductors In nominally doped semiconductors the Fermi level lies between the conduction and valence bands For example in n doped semiconductor as the doping concentration is increased electrons populate states within the conduction band which pushes the Fermi level to higher energy In the case of degenerate level of doping the Fermi level lies inside the conduction band The apparent band gap of a semiconductor can be measured using transmission reflection spectroscopy In the case of a degenerate semiconductor an electron from the top of the valence band can only be excited into conduction band above the Fermi level which now lies in conduction band since all the states below the Fermi level are occupied states Pauli s exclusion principle forbids excitation into these occupied states Thus we observe an increase in the apparent band gap Apparent band gap Actual band gap Moss Burstein shift as shown in the figure Negative Burstein shifts can also occur These are due to band structure changes due to doping 3 References edit Moss T S 1954 The Interpretation of the Properties of Indium Antimonide Proceedings of the Physical Society Section B 67 10 775 782 Bibcode 1954PPSB 67 775M doi 10 1088 0370 1301 67 10 306 ISSN 0370 1301 Burstein Elias 1954 02 01 Anomalous Optical Absorption Limit in InSb Physical Review 93 3 632 633 Bibcode 1954PhRv 93 632B doi 10 1103 PhysRev 93 632 John C Inkson 1984 ch 9 5 page 210 Many Body Theory of Solids Springer ISBN 0 306 41326 4 Further reading editMarius Grundmann 2006 The Physics of Semiconductors Springer Berlin Heidelberg New York Springer ISBN 978 3 540 25370 9 nbsp This electronics related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Moss Burstein effect amp oldid 1170988282, wikipedia, wiki, book, books, library,
