Single photoelectron trapping, storage, and detection in a field effect transistor

We have demonstrated that a single photoelectron can be trapped, stored, and its photoelectric charge detected by a source/drain channel in a transistor. The electron trap can be photoionized and repeatedly reset for the arrival of successive individual photons. This single-photoelectron transistor, operating in the $\ensuremath{\lambda}=1.3\ensuremath{\mu}\mathrm{m}$ telecommunication band, was demonstrated by using a window-gate double-quantum-well InGaAs/InAlAs/InP heterostructure that was designed to provide near-zero electron g factor. In general, g-factor engineering allows selection rules that would convert a photon polarization to an electron-spin polarization. Such a transistor photodetector could be useful for flagging the safe arrival of a photon in a quantum repeater. In the future, the safe arrival of a photoelectric charge would trigger the commencement of the teleportation algorithm in a quantum repeater to be used for quantum telecommunications.