Graphene–silver hybrid devices for sensitive photodetection in the ultraviolet

Abstract

The weak light-matter interaction in graphene can be enhanced with a number of strategies, among which sensitization with plasmonic nanostructures is particularly attractive. This has resulted in the development of graphene-plasmonic hybrid systems with strongly enhanced photodetection efficiencies in the visible and the IR, but none in the UV. Here, we describe a silver nanoparticle-graphene stacked optoelectronic device that shows strong enhancement of its photoresponse across the entire UV spectrum. The device fabrication strategy is scalable and modular. Self-assembly techniques are combined with physical shadow growth techniques to fabricate a regular large-area array of 50 nm silver nanoparticles onto which CVD graphene is transferred. The presence of the silver nanoparticles resulted in a plasmonically enhanced photoresponse as high as 3.2 A W-1 in the wavelength range from 330 nm to 450 nm. At lower wavelengths, close to the Van Hove singularity of the density of states in graphene, we measured an even higher responsivity of 14.5 A W-1 at 280 nm, which corresponds to a more than 10 000-fold enhancement over the photoresponse of native graphene.

Composite‐Scattering Plasmonic Nanoprobes for Label‐Free, Quantitative Biomolecular Sensing

“…Thus, both the CSPs provide enhancement to the weak Raman signal of BSA, with the SNPG sample expectedly giving better enhancement. The enhancement factor obtained here is competitive with those obtained in the literature for similar measurement protocols [65] and, while substantially lower than those recorded from unstructured colloids, is more reproducible and has a well-defined spatial distribution. The latter is a key driver for future translation of such SERS platforms to the clinic or field setting.…”

Investigating photoresponsivity of graphene-silver hybrid nanomaterials in the ultraviolet

“…We believe this arises primarily due to the lower area of surface contact between the nanosphere and the graphene device in the AG 120 device as well as different areas of contact between the two devices, with AG 120 containing larger silver nanospheres with a larger spacing. One can also compare with the device described previously, 16 where the geometries are similar to those of the AG 60 devices, but the maximum responsivity (AG 60) was found to be ∼8 times larger at the same source-drain bias as compared to the previous device. This is probably because of a large number of silver nanoparticles (formed due to unshadowed growth during the GLAD step) present in the AG 60 device (see Fig.…”

“…We further note that the plasmonic maxima shown by the silver-graphene hybrids are of similar spectral characteristics but slightly higher magnitude compared to those of another Ag-graphene device that we had reported previously. 16 More crucially, the enhanced responsivity at λ = 270 nm is in both the silver-graphene hybrids (AG 60 and AG 120) but is not seen in the gold-graphene hybrid (AU 50). This suggests the importance of silver as a material to achieve enhanced sensitivity and rules out the possibility that the anomalously large photoresponsivity is primarily due to strain caused by transferring CVD graphene on nanoparticle arrays.…”

“…In our previous work, 16 we have reported a hybrid graphene photodetector by integrating CVD graphene with a large area hexagonally patterned array of silver nanoparticles. The device shows high responsivity across the UV range with two maxima of 3.2 A/W at the wavelength of λ = 370 nm and 14.5 A/W at λ = 280 nm.…”

Effect of Ag/rGO on the Optical Properties of Plasmon-Modified SnO2 Composite and Its Application in Self-Powered UV Photodetector

“…Owing to the arising demand for precise detection of ultraviolet radiation in civil and military applications, the development of ultraviolet photodetectors with energy efficiency, a sustainable optical energy detection system, and essential and cost-effective wide bandgap material, such as TiO 2 , SnO 2 , ZnO, GaN, SiC, graphene, MoS, and quantum dots, have become vital [1][2][3][4][5][6][7][8]. In addition, the development of modern ultraviolet photodetectors is necessary, because the human body is sensitive to UV radiation that may cause different diseases, including cataracts and skin cancer [9][10][11][12]. Hence, self-powered photoelectrochemical (PEC)-type UV photodetectors (UVPDs) have emerged as a promising optoelectronic device based on photovoltaic effect, that meet the demand of energyefficiency, simple fabrication process, small size, reduced weight, cost-effective, and outstanding photodetection performance for a next generation nanodevice [10,[13][14][15].…”