Abstract
Using a first-principles band structure method, we study how the size of quantum dots affects the stability and transition energy levels of defects in GaAs. We show that, although a negatively charged center is unstable in bulk with respect to the tetrahedral coordinated , it becomes stable when the dot size is small enough. The critical size of the dot is about 14.5 nm in diameter. The reason for the stabilization is the strong quantum-confinement effect, which increases the formation energy of more than that of the defect center. Our studies show that defect properties in quantum dots could be significantly different from those in bulk semiconductors.
- Received 18 January 2005
DOI:https://doi.org/10.1103/PhysRevLett.94.185501
©2005 American Physical Society