Band-gap renormalization in InP/GaxIn1-xP quantum dots

Abstract

A continuous and systematic red shift of the exciton emission energy in small InP/InGaP quantum dots is observed for increasing excitation energies and intensities. Superposed on this red shift, emission energy minima appear which show a one-to-one correspondence to emission intensity maxima as a function of the excitation energy. This band-gap renormalization is attributed to the hybridization of the quantum dot excited states with the wetting layer continuum. Polarization-resolved measurements reveal that the exciton fine structure splitting can be tuned up to 10% in the present case by changing the excitation energy. Possible implications of the present results on the development of entangled photon pair sources are discussed.