Single charge detection of an electron created by a photon in a g-factor engineered quantum dot

We demonstrate that a single photoelectron can be trapped in a single quantum dot, which is formed by gate-defining with a nearly-zero g-factor quantum well, and a charge state can be detected with a quantum point contact without destruction. The detection yield has a peak of 0.27 at the resonant photon energy of the dot exciton in photon flux of 4.1×10−10 W/mm2. The number-resolved counting statistics revealed that the yield for the second electron trap is drastically decreased from that for the first trap because of the Coulomb-blockade effect. The demonstrated function is essential for making a high-fidelity quantum interface.