Optical properties of GaNAs/GaAs structures

We review our recent results on optical characterization of MBE-grown GaNAs /GaAs quantum structures with N content up to 4.5%, by employing photolumin escence (PL), PL excitation, and time-resolved PL spectroscopies. The domin ant PL mechanism has been determined as recombination of excitons trapped b y potential fluctuations of the band edge, due to composition disorder and strain nonuniformity of the alloy. The estimated value of the localization potential is around 60 meV for the low-temperature grown structures and can be reduced by increasing the growth temperature or using post-growth rapid thermal annealing (RTA). (C) 2001 Elsevier Science S.A. All rights reserve d.