High-performance graphene-quantum-dot photodetectors

Abstract

Graphene quantum dots (GQDs) have received much attention due to their novel phenomena of charge transport and light absorption/emission. The optical transitions are known to be available up to ~6 eV in GQDs, especially useful for ultraviolet (UV) photodetectors (PDs). Thus, the demonstration of photodetection gain with GQDs would be the basis for a plenty of applications not only as a single-function device in detecting optical signals but also a key component in the optoelectronic integrated circuits. Here, we firstly report high-efficient photocurrent (PC) behaviors of PDs consisting of multiple-layer GQDs sandwiched between graphene sheets. High detectivity (>1011 cm Hz1/2/W) and responsivity (0.2 ~ 0.5 A/W) are achieved in the broad spectral range from UV to near infrared. The observed unique PD characteristics prove to be dominated by the tunneling of charge carriers through the energy states in GQDs, based on bias-dependent variations of the band profiles, resulting in novel dark current and PC behaviors.

Dirac point induced ultralow-threshold laser and giant optoelectronic quantum oscillations in graphene-based heterojunctions

“…Interestingly, a pure diode like behavior in the I–V curve is observed without any indication of oscillation (see Supplementary Fig. 16 ), which is consistent with previous reports of graphene- and rGQD-based sandwiched devices 23 , 24 .…”

“…When the bias voltage is tuned, the E F of the subsequent graphene changes monotonically. The E F close to a certain energy state of GQDs thus causes a resonant tunneling of electrons 21 – 24 as shown in Fig. 1d .…”

Size‐Controlled Graphene Nanodot Arrays/ZnO Hybrids for High‐Performance UV Photodetectors

“…Many researches have been conducted to open the band gap by fabricating nanostructures such as graphene nanodots (GNDs),3 graphene nanomeshes,4 and graphene nanoribbons 5. Compared with graphene, GNDs have excellent optical and electrical properties, which are tunable depending on size and shape,6 thus holding promising application prospects in photoelectric devices 7…”

Energy transfer from an individual silica nanoparticle to graphene quantum dots and resulting enhancement of photodetector responsivity

“…GQDs typically show strong optical absorption in the near-ultraviolet (UV) region, with a tail extending out into the visible range 20 21 22 . Variously-sized GQDs with different photoluminescence (PL) colors ranging from UV to near-infrared (NIR) region have been prepared via various synthetic approaches 19 21 22 23 24 25 . Adjusting the size of GQDs is therefore expected to enhance the FRET efficiency as donors or acceptors.…”