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Proceedings Paper

Photoemission from periodic structure of graded superlattices under magnetic field
Author(s): Kamakhya Prasad Ghatak
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Paper Abstract

With the recent advances of MBE and MOCITD techniques, it has been possible to grow semiconductor superlattices (SL's) composed of alterior e layers of two different degenerate materials with controlled thickness. The SL has found wide applicants in many new device structures, such as photodetectors, avalanche photo-diodes, tunneling devices, transistors, light-emitters etc. In addition to the usual Ill-V SL' s having Kane type energy bands, the SL's with more complex structures such as II...VI, PbPe/ PbSnTe, strained layer and IIgTe/CdTe SL' s have been proposed with the assumption that the interfaces between the layers are sharply defined with zero thicknesses, so as to be devoid of any interface effect. As the potential form changes from a well to a barrier, an intermediate potential region exists for the carriers. Thus the influence of the finite thickness of the interface on the electron dispersion relation becomes iniportant. It appears from the literature that the photo-emission from small gap SL's with graded interface has yet to be reported under quantizing magnetic field. In this paper, an attempt is made for the first time to investigate the photo emission from such heterostructures and compare the same with the bulk specimens of the constituent materials by formulating the respective magneto-dispersion relations. It is found that the photoemission exhibits oscillatory dependence with inverse quantizing magnetic field and the electron concentration respectively in all the cases. The oscillations in HgPe/CdTe superlattices show up much more significantly as compared to other systems even in the presence of broadening. In addition, the well-known expressions for the bulk specimens of non-degenerate parabolic materials have also been derived as special cases from our generalized expressions.

Paper Details

Date Published: 1 October 1991
PDF: 12 pages
Proc. SPIE 1545, International Conference on the Application and Theory of Periodic Structures, (1 October 1991); doi: 10.1117/12.49428
Show Author Affiliations
Kamakhya Prasad Ghatak, Univ. of Jadavpur (India)

Published in SPIE Proceedings Vol. 1545:
International Conference on the Application and Theory of Periodic Structures
Jeremy M. Lerner; Wayne R. McKinney, Editor(s)

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