Heterostructured hBN‐BP‐hBN Nanodetectors at Terahertz Frequencies

Abstract

By reassembling thin isolated atomic planes of hexagonal borum nitride (hBN) with a few layer phosphorene black phosphorus (BP), hBN/BP/hBN heterostructures are mechanically stacked to devise high-efficiency THz photodetectors operating in the 0.3-0.65 THz range, from 4 K to 300 K, with a record signal-to-noise ratio of 20 000.

Towards sensitive terahertz detection via thermoelectric manipulation using graphene transistors

“…On one hand, the device response mainly relies on the power density focused onto the channel rather than the antenna area. In our case, the antenna was an order of magnitude larger than previously reported ones 16,[18][19][20] . Indeed, the antenna can retain a superior radiation funneling capability with a much smaller effective antenna area, even though it is smaller than the diffraction limit area defined by S~(λ/2n sub ) 2 (λis the wavelength and n sub 3.5 is the refractive index of the substrate; also see the Supporting Information for a detailed calculation of the effective antenna area).…”

“…In addition, the minimal NEP of our devices was 0.1nW/Hz 0.5 when operating in photovoltaic mode. For the photoconductive mode, the NEP was approximately five times larger (~0.5 nW/ Hz 0.5 ), which is also moderate compared with recently reported results 18,20 . Therefore, switching between different working modes can be achieved within a single device, depending on the configuration of the electrical contacts and the subsequent readout set-up.…”

“…Graphene-based THz detectors have been reported to exhibit suitable performance in the framework of plasma self-mixing and thermoelectric effects. The plasma self-mixing effect can be achieved via the asymmetrical antenna coupling of a THz field between a source/drain and gate, during which the nonlinear rectification of carrier transport leads to direct detection with a responsivity of approximately 0.04~20 V/W [19][20][21][22] . Moreover, thermoelectric THz detection in graphene can be achieved by asymmetric contacting, which produces a Seebeck coefficient difference and direct photocurrent along the channel due to metal-induced asymmetrical doping 18 , and the responsivity can reach as high as 15 V/ W. While high-performance graphene-based devices have become increasingly critical to satisfying the requirements of everyday applications, the current implementation of direct THz detection is hindered by the lack of sufficient photoelectric gain 23 .…”

Temperature dependence of Raman-active phonons and anharmonic interactions in layered hexagonal BN

“…In these layered heterostructures, the atomically flat interfaces arising from van der Waals bonding are free of surface states and yield improved electron mobilities [9]. Quite recently, a h-BN/black phosphorous/h-BN THz photodetector has been demonstrated, showing a remarkably high signal-to-noise ratio and high values of the field-effect hole mobility [10]. Furthermore, the basal plane thermal conductivity of h-BN is two orders of magnitude higher than that of SiO 2 , and therefore the h-BN dielectric layer enhances the lateral heat spreading from the conducting active layer thus helping to efficiently dissipate heat [11], which is critical for close packed electronic devices.…”

Dual-Polarized Multi-Band Infrared Energy Harvesting Using H-Shaped Metasurface Absorber

“…An optical rectenna consists of a nano antenna to capture solar radiation and a rectifier, Metal Insulator Metal (MIM) diode [8], to convert the captured energy to useful DC power. The recent advancements in nanotechnology enabled the possibility to fabricate optical antennas and other terahertz devices [9][10][11] with a broad range of potential applications [12][13][14][15][16]. The fact that optical rectennas can capture solar energy during the day and night with wideband reception and higher theoretical conversion efficiency make them advantageous over photovoltaic technology.…”