Graphene/PbS quantum dot hybrid structure for application in near-infrared photodetectors

Abstract

A graphene-PbS quantum dot (QD) composite for application in high-performance near-infrared (NIR) photodetectors (PDs) is proposed in this study. A single-layer graphene flake and oleic acid-capped PbS QD composite is fabricated through the conventional sonication process, in hexane solution. Field emission scanning electron microscopy images of the graphene-PbS QD composite dispersed on a glass substrate confirm that the composite contains both aggregated graphene flakes and single-layer graphene with wrinkles; Transmission electron microscopy images reveal close packing with uniform size. The increased absorbance and quenched photoluminescence intensity of the graphene-PbS QD composite supports enhanced photoinduced charge transfer between graphene and the PbS QDs. Moreover, the specific Raman mode of the PbS QDs, embedded in the spectrum, is enhanced by combination with graphene, which can be interpreted by SERS as relevant to the photoinduced charge transfer between the Pbs QDs and graphene. For device application, a PD structure comprised by graphene-PbS QDs is fabricated. The photocurrent of the PD is measured using a conventional probe station with a 980-nm NIR laser diode. In the fabricated PD comprising graphene-PbS QDs, five-times higher photocurrent, 22% faster rise time, and 47% faster decay time are observed, compared to that comprising PbS QDs alone. This establishes the potential of the graphene-PbS QD composite for application in ultrathin, flexible, high-performance NIR PDs.

An Irradiance‐Adaptable Near‐Infrared Vertical Heterojunction Phototransistor

“…[20,22] The Raman spectrum of the graphene-PbS hybrid film was determined and shown in Figure 1b, demonstrating the characteristic peaks of both the monolayer graphene and PbS. [23] The cross-sectional scanning electron microscopy (SEM) image of the hybrid film in Figure 1c shows about 124 nm thickness of the PbS QDs film. Finally, the same graphene strip-Au pad structure was prepared above the QDs film using the same procedure as the bottom one.…”

2D Materials for Efficient Photodetection: Overview, Mechanisms, Performance and UV-IR Range Applications

“…Graphene is a good option for room-temperature photodetection purpose because of its several virtues which are greater mobility, less carrier transit time, and good susceptibility to the electrostatic disturbance caused by photogenerated surface carriers. Colloidal QDs synthesized by PbS ( Sun et al, 2012 ; Jeong et al, 2020 ) shown in Figure 7C ( Konstantatos et al, 2012 ) are an example of graphene-sensitized light-absorbing particles. Photon detection at weak incident light intensities, especially at single-photon levels, necessitates a gain mechanism capable of providing numerous electrical carriers for each individual illuminated photon.…”

Near‐Infrared to Visible Light Converter by Integrating Graphene Transistor into Perovskite Quantum Dot Light Emitting Diodes

“…Combining these two promising substances can enhance the photoresponsivity and shorten the response time of the photodetector devices. [ 15–17 ] Perovskite quantum dots (P‐QDs) light‐emitting diode (QLEDs) exhibit luminescent efficiency comparable to the organic light emitting diodes (OLEDs), narrow emission bandwidth, and color‐tunable wavelength, making them promising candidates for next‐generation lighting sources and information display devices. [ 18–20 ]…”

“…Combining these two promising substances can enhance the photoresponsivity and shorten the response time of the photodetector devices. [15][16][17] Perovskite quantum dots (P-QDs) light-emitting diode (QLEDs) exhibit luminescent efficiency comparable to the organic light emitting diodes (OLEDs), narrow emission bandwidth, and color-tunable wavelength, making them promising candidates for next-generation lighting sources and information display devices. [18][19][20] Herein, we report a near-infrared (NIR) to visible light converter (NVLC), which integrates the inverted perovskite QLEDs with the hybrid PbS QDs/graphene transistors through multiple micro-nano manufacturing processes.…”