ISSN:
1432-0630
Keywords:
73.20D
;
73.20H
;
78.65
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The luminescence associated with residual carbon acceptors in type-I (direct-gap) ultrathin-layer superlattices (UTLS) with well and barrier widths of 22.7〈L z〈25.2 Å and 11.5〈L b〈14.0 Å, respectively, is composed two lines reflecting the on-center and on-edge state of the impurities. In these narrow wells the on-center acceptor binding energy increases to 60 meV in agreement with theoretical calculations for GaAs single quantum wells using a valence band offset of 500 meV. While the binding energy of the on-center state does not vary significantly within the studied L z and L b range, the on-edge state shows a strong dependence on the very narrow barrier width. This increase of the acceptor binding energy makes the energy position of the impurity-related luminescence in UTLS very sensitive to the actual barrier height. Investigation of the impurity-related luminescence thus provides a versatile tool to determine the band offset ratio at the heterojunction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00323847
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