Electronic Resource
Woodbury, NY
:
American Institute of Physics (AIP)
Applied Physics Letters
52 (1988), S. 969-971
ISSN:
1077-3118
Source:
AIP Digital Archive
Topics:
Physics
Notes:
HgTe-CdTe superlattices of high crystalline quality, and with negligible interdiffusion, have been successfully grown at low substrate temperatures (150–170 °C) by molecular beam epitaxy. Optical spectra exhibiting multiple steplike absorption edge features have been measured on as-grown and thermally annealed samples. The data provide valuable information on the superlattice subband structure when coupled with a suitable model. These results then can be used to obtain semiquantitative measures of layer interdiffusion along with such quantities as valence-band offset and strain. To observe subband structure in the optical data, it is necessary to fabricate samples having homogeneous HgTe and CdTe layer thicknesses in the superlattice growth direction. Homogeneity of layers was achieved by carefully controlling elemental source fluxes and shutter times during the epitaxial growth process. Substantial changes in the subband-related absorption structure could be induced by annealing the superlattice samples at temperatures just slightly above the growth temperature. An observed shift of the fundamental absorption edge to higher energy, as well as an apparent broadening of the subband absorption structure upon annealing, can be explained by interdiffusion of HgTe and CdTe layers.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.99244
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