Patent ID: 7462859

Claim:
A photon detector comprising a body of semiconductor material having a quantum well region disposed in barrier material in said body, said body having first and second electrodes formed thereon, the first electrode forming an isolation electrode for defining, when negatively energized, an extent of a quantum well in said body and the second electrode being positioned above a location where an electrostatic quantum dot is defined in said quantum well in response to positive energization of said second electrode, the quantum well occurring in a quantum well region defined by at least three layers of material including: (i) a central layer at least partially disposed within the quantum well, and (ii) two outer layers also at least partially disposed within the quantum well, the two outer layers of the quantum well region having a relatively low conduction band minimum compared the barrier material which has a relatively high conduction band minimum, the central layer having a conduction band minimum between the relatively high conduction band minimum of the barrier material and relatively low conduction band minimum of the two outer layers, and wherein an effective, weighted g-factor for the detector is sufficiently close to zero that the Zeeman energy is less than a linewidth, expressed in terms of energy, of photons to be detected by the detector, the central layer and the two outer layers being sufficiently thin that only a single, common quantum well occurs with respect to said quantum dot.