Photoluminescence studies of GaAs quantum dots grown by droplet epitaxy

We have investigated post-annealing effects of photoluminescence (PL) prope rties in GaAs/AlGaAs QDs fabricated by modified droplet epitaxy. The anneal ing temperatures were changed between 520 degreesC and 760 degreesC. The PL intensity of QDs: increased drastically with the increase of annealing tem perature. The PL intensity of QDs after the annealing at 760 degreesC was e nhanced by two orders of magnitude as compared to that of before post-annea ling. This sample showed a distinct PL peak even at the room temperature. W ith the increase of annealing temperatures, the peak energy shifted from 1. 646 to 1.749 eV, continuously. These effects may be caused by improving the crystallinity of QDs systems and the size reduction and:or changing the co mposition of QDs by the post-annealing. (C) 2001 Elsevier Science B,V. All rights reserved.