Detecting Single Photons Using Capacitive Coupling of Single Quantum Dots

Capturing single photons through light–matter interactions is a fascinating and important topic for both fundamental research and practical applications. The light–matter interaction enables the transfer of the energy of a single photon (∼1 eV) to a bound electron, making it free to move either in the crystal lattice or in the vacuum. In conventional single photon detectors (e.g., avalanche photodiodes), this free electron triggers a carrier multiplication process which amplifies the ultraweak signal to a detectable level. Despite their popularity, the timing jitter of these conventional detectors is limited to tens of picoseconds, mainly attributed to a finite velocity of carriers drifting through the detectors. Here we propose a new type of single photon detector where a quantum dot, embedded in a single-electron transistor like device structure, traps a photogenerated charge and gives rise to a sizable voltage signal (∼7 mV per electron or hole by simulation) on a nearby sense probe through capacitive ...