Graphene quantum dot arrays: Pros and cons of photodetection in the Coulomb blockade regime

Abstract

Photon detection at elevated temperatures is a long-term debatable issue. Efforts are on to extend the temperature range beyond RT and this has been accomplished to a certain extent by combining two factors –(i) device’ structural design, and (ii) degree of quantum confinement. Zero-dimensional quantum confined semiconductor heterostructures have been investigated both theoretically and experimentally for quite some time; but no reports are available whether Quantum Dots is worthy for photodetection in Coulomb blockade regime and possess, if any, virtue to extend the operating temperature.In this report, Graphene Quantum Dots array (GQDs), were subjected to detect high photon density in the temperature range 77–623 K to check the sustainability of its noise free and quality performance. Stable performance is found up to 530 K beyond which the detector performance got badly affected owing to carrier transport and relaxation mechanisms. Appreciable detection performance is found in the Coulomb blockade (CB) regime (93–138 K) where carrier charging and tunneling through QDs control the detection mechanism. In non-CB regime (138–623 K), normal activation energy induced photodetection takes place. Detector performance shows that the user can opt for both the temperature regimes, though there are marked differences between them in terms of detection mechanism and performance.