Interactions of metallic quantum dots on a semiconductor substrate

Experiments have shown that uniform metallic quantum dots may self-assemble on a semiconductor substrate. The observation calls for a repulsive force when the dots are close. In a traditional quantum dot system, such as Ge dots on a Si substrate, such an action is achieved by elastic interaction. This paper proposes a mechanism for metallic dots without coherent lattice or lattice mismatch, so that elastic effect may not account for the phenomena. We show that electric double layers due to contact potential can lead to size-dependent repulsion, which counterbalances van der Waal attraction and determines feature sizes.