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Optical Properties of Arrays of Quantum Dots
E.V. Tsiper and A.L. Efros
Department of Physics, University of Utah, Salt Lake City, UT 84112
The theory of PL and PLE spectra of large arrays of isolated
self-organized quantum dots is developed to interpret the recent
photoluminescence data [1]. It is assumed that all dots contribute
independently to optical processes and that emission of light occurs
from the ground state of each dot only. The theory explains the large
observed shift between the PL and PLE peaks. It is shown that the
shift is equal to the average distance between the ground and first
excited states of the dots. It is also shown that PL and PLE data give
statistical correlation between positions of the ground and excited
energy levels in the presence of disorder. The lineshape of the
spectra is calculated for the case of alloy disorder. The influence of
the rough boundary of quantum dot is also discussed. The calculated
PL and PLE lineshapes are in good agreement with the experimental data
[1]. We also predict an unusual sensitivity of the lineshape to the
magnetic field. This happens because the dots that accidentally have
small disorder-induced splitting of the excited level are strongly
affected by a relatively weak magnetic field.
Financed by QUEST of UCSB subagreement KK3017.
[1] S. Fafard, D. Leonard, J. L. Merz, and P. M. Petroff, Appl.
Phys. Lett. {\bf 65}, 1388, 1994.
38th Electronic Materials Conference, Santa Barbara, June 26-28, 1996.
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