Gate-defined quantum-dot devices realized in InGaAs/InP by incorporating a HfO_2 layer as gate dielectric

摘要

Gate-defined quantum dots in an InGaAs/InP heterostructure are realized by incorporating a high-κ HfO_2 material as a gate dielectric using atomic layer deposition. The fabricated quantum-dot devices show Coulomb blockade effect at low temperature. The Coulomb blockade current peaks are found to shift in pairs with the magnetic field applied perpendicular to the quantum-dot plane, due to the filling of electrons into spin-degenerate orbital states. When the magnetic field is applied parallel to the quantum-dot plane, spin splittings of orbital states are observed and the extracted effective g-factors are found to be different for different orbital states.