Plasmonically enhanced mid-IR light source based on tunable spectrally and directionally selective thermal emission from nanopatterned graphene

Abstract

We present a proof of concept for a spectrally selective thermal mid-IR source based on nanopatterned graphene (NPG) with a typical mobility of CVD-grown graphene (up to 3000 $$\hbox {cm}^2\,\hbox {V}^{-1}\,\hbox {s}^{-1}$$ cm 2 V - 1 s - 1 ), ensuring scalability to large areas. For that, we solve the electrostatic problem of a conducting hyperboloid with an elliptical wormhole in the presence of an in-plane electric field. The localized surface plasmons (LSPs) on the NPG sheet, partially hybridized with graphene phonons and surface phonons of the neighboring materials, allow for the control and tuning of the thermal emission spectrum in the wavelength regime from $$\lambda =3$$ λ = 3 to 12 $$\upmu$$ μ m by adjusting the size of and distance between the circular holes in a hexagonal or square lattice structure. Most importantly, the LSPs along with an optical cavity increase the emittance of graphene from about 2.3% for pristine graphene to 80% for NPG, thereby outperforming state-of-the-art pristine graphene light sources operating in the near-infrared by at least a factor of 100. According to our COMSOL calculations, a maximum emission power per area of $$11\times 10^3$$ 11 × 10 3 W/$$\hbox {m}^2$$ m 2 at $$T=2000$$ T = 2000 K for a bias voltage of $$V=23$$ V = 23 V is achieved by controlling the temperature of the hot electrons through the Joule heating. By generalizing Planck’s theory to any grey body and deriving the completely general nonlocal fluctuation-dissipation theorem with nonlocal response of surface plasmons in the random phase approximation, we show that the coherence length of the graphene plasmons and the thermally emitted photons can be as large as 13 $$\upmu$$ μ m and 150 $$\upmu$$ μ m, respectively, providing the opportunity to create phased arrays made of nanoantennas represented by the holes in NPG. The spatial phase variation of the coherence allows for beamsteering of the thermal emission in the range between $$12^\circ$$ 12 ∘ and $$80^\circ$$ 80 ∘ by tuning the Fermi energy between $$E_F=1.0$$ E F = 1.0 eV and $$E_F=0.25$$ E F = 0.25 eV through the gate voltage. Our analysis of the nonlocal hydrodynamic response leads to the conjecture that the diffusion length and viscosity in graphene are frequency-dependent. Using finite-difference time domain calculations, coupled mode theory, and RPA, we develop the model of a mid-IR light source based on NPG, which will pave the way to graphene-based optical mid-IR communication, mid-IR color displays, mid-IR spectroscopy, and virus detection.

Analysis on the Electrostatic Doping and Several Alternative Devices

“…Compared to Si 3 N 4 and standard SiO 2 , the electron migration rate in graphene is reduced due to the introduction of additional scattering centers. This method is optional for controlling the concentration and polarity of carriers in graphene and provides conditions for the manufacture of devices with complementary phenomenon, access zones or high conductivity channels, low resistance at contact or low carrier density [3].…”

“…These methods include devices, such as Graphene ED [3], SB-MOSFETs, reconfigurable FET [2], FD semiconductor and 2D materials [4], and electron-hole bilayer (EHB)-based TFET [5]. At the same time, the system on ED has been built, which has not been implemented.…”

Numerical Simulations of Nanolayered Heterostructures of Nanopatterned Graphene and Vanadium Oxide for Mid-Infrared Photodetectors Operating Close to Room Temperature

“…This interaction is so weak that the IMT cannot be achieved. That is why in the wavelength regime of 8–12 μm the photodetection is based purely on the bolometric effect in the semiconducting phase of VO 2 . , VO 2 -based heterostructures have shown an improvement in photoresponse in the visible and ultraviolet regions. − Here, by adding a single layer of nanopatterned graphene (NPG) on top of a layer of VO 2 , we present the model of a photodetector that not only greatly enhances the absorption of mid-IR light energy in the longer wavelength regime from λ = 6 μm and exceeding 12 μm but also narrows the absorption bandwidth to 0.1 μm within the mid-IR range of 3–12 μm, thereby enabling plasmonically enhanced spectrally selective absorption of mid-IR light for the IMT effect in a heterostructure made of NPG and VO 2 .…”

Theoretical Model of a Plasmonically Enhanced Tunable Spectrally Selective Infrared Photodetector Based on Intercalation-Doped Nanopatterned Multilayer Graphene

“…Because of the weak absorbance of pristine graphene of around 2%, we created nanopatterned CVD-grown single-layer graphene (NPG) that exhibits absorbance exceeding 60% in the long-wavelength infrared (LWIR) regime between λ = 8 and 12 μm. , Recently, we showed that NPG with smaller sizes of hexagonally arranged holes and smaller lattice constants exhibits absorbance of 80% in the mid-wavelength (MWIR) regime between λ = 3 and 8 μm . Because of the resolution limit of e-beam lithogaphic systems it is currently impossible to create smaller nanopatterns for increasing the absorbance of NPG at shorter wavelengths.…”

“…1,2 Recently, we showed that NPG with smaller sizes of hexagonally arranged holes and smaller lattice constants exhibits absorbance of 80% in the midwavelength (MWIR) regime between λ = 3 and 8 μm. 3 Because of the resolution limit of e-beam lithogaphic systems it is currently impossible to create smaller nanopatterns for increasing the absorbance of NPG at shorter wavelengths.…”