Electric field induced removal of the biexciton binding energy in a single quantum dot.

We control the electrostatic environment of a single InAsP quantum dot in an InP nanowire with two contacts and two lateral gates positioned to an individual nanowire. We empty the quantum dot of excess charges and apply an electric field across its radial dimension. A large tuning range for the biexciton binding energy of 3 meV is obtained in a lateral electric field. At finite lateral electric field the exciton and biexciton emission overlap within their optical line width resulting in an enhancement of the observed photoluminescence intensity. The electric field dependence of the exciton and biexciton is compared to theoretical predictions and found to be in good qualitative agreement. This result is promising toward generating entangled photon pairs on demand without the requirement to remove the anisotropic exchange splitting from asymmetric quantum dots.