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Improvement in size distribution and optical properties of InAs/GaAs QDs by post growth thermal treatment
Author(s) -
Saravanan Shanmugam,
Harayama Takashisa
Publication year - 2009
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200880590
Subject(s) - photoluminescence , quantum dot , excited state , materials science , annealing (glass) , optoelectronics , blueshift , quantum well , atomic physics , optics , physics , laser , composite material
We investigated the effect of rapid thermal annealing from 700 °C to 950 °C on stacked InAs/GaAs quantum dots (QDs) covered with GaAs and In 0.19 Ga 0.81 As layers. Large blue‐shift of the energy positions nearly 380 meV (1187 nm to 870 nm) have been observed in InGaAs capped samples together with improvement in the photoluminescence integrated intensity of more than five times. The strong narrowing of the photoluminescence line‐width in both GaAs (as narrow as 8 meV) and InGaAs capped samples show an improvement of the size distribution of the QDs. In addition, a significant reduction of the energy spacing (Δ E 2–1 ) between ground state and first excited state emissions were found in both GaAs and InGaAs capped quantum dots due to interface inter‐diffusion induced by thermal treatment. The excited state filling experiments for InGaAs capped sample annealed at 950 °C exhibits quantum well like behavior where as, the GaAs capped sample shows a shoulder in high energy side might be due to first excited state of QDs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)