SELF-LIMITED FACET GROWTH FOR GAAS TETRAHEDRAL QUANTUM DOTS

When metal-organic chemical vapor deposition is used to fabricate GaAs tetrahedral quantum dots by selective epitaxy on triangular windows of (111)B GaAs, there is a condition under which growth automatically stops before the tetrahedral shape is completed. Under a constant growth condition, the size of self-stopped (111)B triangular top facets is extremely uniform and is not influenced by fluctuation of mask window size. Experiments showing that the size of top facet increases with increasing substrate temperature and with decreasing trimethylgallium partial pressure imply that the size is determined by the submicron diffusion length of Ga atoms on (111)B GaAs surface.