Sensitive detection of photoexcited carriers by resonant tunneling through a single quantum dot

TL;DR

This paper demonstrates a quantum dot device that detects photoexcited holes via resonant tunneling, enabling high on/off current switching for potential photon counting applications.

Contribution

It introduces a method to detect photoexcited carriers using resonant tunneling through a single quantum dot with high sensitivity and controllability.

Findings

Resonant tunneling current is highly sensitive to nearby photoexcited holes.

The device achieves an on/off ratio greater than 50.

The system can be reset with a bias voltage pulse.

Abstract

We show that the resonant tunnel current through a single energy level of an individual quantum dot within an ensemble of dots is strongly sensitive to photoexcited holes that become bound in the close vicinity of the dot. The presence of these holes lowers the electrostatic energy of the quantum dot state and switches the current carrying channel from fully open to fully closed with a high on/off ratio (> 50). The device can be reset by means of a bias voltage pulse. These properties are of interest for charge sensitive photon counting devices.