We study the GaSb/GaAs nanostructures (NSs) grown by droplet epitaxy technique with various Ga amounts. Ga amount deposited on the GaAs (001) substrate was varied between 3-5 ML to form the different size and density of liquid Ga droplets. The Sb flux was subsequently irradiated to crystallize the droplets. Morphology of GaSb NSs was investigated by atomic force microscopy (AFM). Quantum rings were obtained after crystallizing 3-ML Ga droplets, whereas some kind of quantum dots were formed after crystallizing 4-and 5-ML Ga droplets. The formation mechanisms leading to the different structure are discussed. The photoluminescence (PL) measurement was performed to examine the optical properties of GaSb/GaAs NSs.
Self-assembly of quantum dots and rings by droplet epitaxy and their optical properties