Effects of annealing on self-assembled InAs quantum dots and wetting layer in GaAs matrix
Post-growth thermal annealing effects on InAs/GaAs quantum dots (QDs) near Stransky-Krastanow transformation were investigated. Self-assembled QDs of average size of about 10 nm were grown by metal-organic vapor phase epitaxy. The photoluminescence (PL) due to emission from QDs as well as two peaks due to emission from the strained InAs wetting layer (WL) were observed in as-grown samples. Bimodal structure of the WL PL was attributed to WL regions of different thickness. There was almost no difference in the PL spectrum after 30 s annealing at 600 C. However, annealing at temperatures in the range between 700 C and 950 C resulted in quenching of the PL from QDs and the thinner WL. The PL peak from the new, thicker WL blue-shifted and narrowed with increasing annealing temperature. This behavior was in agreement with TEM observations. Complete dissolution of the QDs and substantial broadening of the WL was observed. All our results indicate that thermally induced modifications of the WL rather than QDs can be responsible for the blue-shift and narrowing of the PL peaks in structures containing InAs QDs.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director, Office of Science. Office of Basic Energy Studies. Division of Materials Sciences; Polish Committee for Scientific Research, Grant No. 7T08A04017 (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 783742
- Report Number(s):
- LBNL-47765; R&D Project: 513340; TRN: US200302%%444
- Resource Relation:
- Conference: 2000 Materials Research Society Fall Meeting, Boston, MA (US), 11/27/2000--12/01/2000; Other Information: PBD: 18 Apr 2001
- Country of Publication:
- United States
- Language:
- English
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