Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
HL: Halbleiterphysik
HL 12: Poster I
HL 12.57: Poster
Montag, 8. März 2004, 16:30–19:00, Poster A
The manipulation of the energy levels in InAs-quantum dots by thermal treatment — •Victorina Stavarache, Dirk Reuter, and Andreas Wieck — Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum, Germany
We have investigated the effect of thermal treatment on QD samples by photoluminiscence (PL) measurements. The sample structure contains 10 QD layers separated by 100nm GaAs. The QDs have been grown by MBE on a semi-insulating GaAs(100) substrate. After growth, the 4x4 samples were cleaved and annealed for 30s at temperatures from 800oC to 960oC using a rapid thermal annealing system. With increasing annealing temperature, the PL peaks show a shift to smaller wavelength. Simultaneously, the energy separation between adjacent peaks becomes smaller. These observation point to an increase of the energy difference between electron and hole levels (from E=1,054eV for unannealed sample to E=1,389eV for an annealing temperature of 960oC) whereas the intersublevel spacing decreases (from ΔE=52,7meV for unannealed sample to ΔE=17,3meV for an annealing temperature of 960oC). We explain this blueshift due to the diffusion of the Ga atoms into the QD and the out diffusion of the In atoms from the QD during the thermal annealing process.