Biexciton binding energy control in site-selected quantum dots

A unique nanotemplate deposition technique is utilized in growth of semiconductor quantum dots which enables precise control over the dot dimensions and nucleation site. Here, we demonstrate tuning of the biexciton binding energy in a single, site-selected InAs/InP quantum dot through manipulation of the nanotemplate dimensions and thus, dot size. A monotonic decrease of the biexciton binding energy from the binding to anti-binding regime through zero is observed with increasing dot size. Piezoelectric fields in large quantum dots are suggested as the mechanism to obtain an unbound biexciton state. The tunability of the biexciton binding energy demonstrated here for a deterministically positioned quantum dot is an important step towards a scalable route in the generation of entangled photon pairs that emit around the telecommunications band of 1.55 mu m.