The Surface Morphology and Optical Characteristics for InAs/GaAs Quantum Dots with Different Coverage

In this study, the influence of varied InAs coverage on InA/GaAs quantum dots (QDs) formation was investigated. With the thickest coverage of 2.6 monolayers (ML), two-group size distribution of QDs is observed. In this sample, extremely large and irregular shaped islands with height over 20 nm were formed, which could be produced by the coalescence of neighboring islands. And these islands were thought to be dislocated. However, other samples with lower coverage showed a more uniform distribution of QD size. And the red shift of ground state transition with increasing coverage can be attributed to the increasing height of QDs. QDs density decreases with increasing InAs coverage.