Operating Temperature Dependence of QDOGFET Single-Photon Detectors

Abstract

We report on the temperature dependence of the photosensitivity of a quantum dot, optically gated, field-effect transistor (QDOGFET) that uses self-assembled semiconductor quantum dots embedded in a high-electron-mobility transistor to detect individual photons of light. Paramount to the operation of the device is differentiating weak, photo-induced signals from random fluctuations associated with electrical noise. To date, QDOGFETs have only been shown to be single-photon sensitive when cooled to 4 K. Here, we study noise spectra of a QDOGFET for sample temperatures ranging from 7-60 K and discuss how the noise affects the sensitivity of the device when operated at elevated temperatures. We show that the QDOGFET maintains single-photon sensitivity for temperatures up to 35-40 K where increases in operating temperature can be traded for decreases in signal-to-noise ratio.