Quantum dots induced by strain from buried and surface stressors

Quantum dots can be induced in a quantum well by strain from a buried, self-assembled dot or from a stressor on the surface. The elastic fields are shown to be significantly different in their ability to trap carriers. There is no dilation around a buried dot, which therefore has no effect on electrons, and the axial strain repels both holes and excitons. A stressor on the surface, in contrast, produces dilation that can confine all carriers. In both cases, the piezoelectric potential may trap electrons and holes separately in space, storing long-lived spatially indirect excitons.