Optical behavior of GaAs/AlGaAs ringlike nanostructures

Atomic force microscopy and photoluminescence (PL) measurements were carried out to investigate the role of the morphology of GaAs/Al0.3Ga0.7As ringlike nanostructures on their optical properties. A small amount of Ga material (less than three monolayers) was used to fabricate single ringlike and double ringlike (DRL) nanostructures using droplet epitaxy technique. The height of the ringlike nanostructures increased with the increase of the Ga material while the corresponding PL emission energy was found to decrease as the ringlike nanostructure height increased. The PL peak energy showed a blueshift with increasing excitation intensity that can be understood as due to state filling while increasing temperature showed that the peak energy of the larger DRL nanostructures redshifts at a lower rate than the small ones due to larger confinement potential and lower energy emissions. (c) 2007 American Institute of Physics.