Radiative lifetime of localized excitons in GaAs quantum dots

✍ Scribed by T. Kono; Y. Nagamune; M. Nishioka; Y. Arakawa

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 132 KB
• Volume: 17
• Category: Article
• ISSN: 0749-6036
• DOI: 10.1006/spmi.1995.1016

✦ Synopsis

We have investigated the exciton radiative lifetime in (\mathrm{GaAs}) quantum dots fabricated by metal organic chemical vapor selective growth technique. The radiative lifetime (\tau_{\mathrm{r}}) can be obtained from the results of photoluminescence(PL) and timeresolved PL measurements. At low temperature below (30 \mathrm{~K}, \tau_{\mathrm{r}}) is almost constant ( (\sim 450 \mathrm{psec}) ) and longer than that in quantum wells. This result can be explained by reduced exciton coherence volume with the change of the dimensionality of confinement. The increase of (\tau_{\mathrm{r}}) above (30 \mathrm{~K}) results from the contribution of higher sub-levels. By considering the thermal energy at (30 \mathrm{~K}), effective lateral size of quantum dots can be estimated as (\sim 80 \mathrm{~nm} \times 80 \mathrm{~nm}), which is smaller than the size determined by SEM observation.