Terahertz bolometric detectors based on graphene field-effect transistors with the composite h-BN/black-P/h-BN gate layers using plasmonic resonances

Abstract

We propose and analyze the performance of terahertz (THz) room-temperature bolometric detectors based on the graphene channel field-effect transistors (GC-FET). These detectors comprise the gate barrier layer (BL) composed of the lateral hexagonal-boron nitride black-phosphorus/hexagonal-boron nitride (h-BN/b-P/h-BN) structure. The main part of the GC is encapsulated in h-BN, whereas a short section of the GC is sandwiched between the b-P gate BL and the h-BN bottom layer. The b-P gate BL serves as the window for the electron thermionic current from the GC. The electron mobility in the GC section encapsulated in h-BN can be fairly large. This might enable a strong resonant plasmonic response of the GC-FET detectors despite relatively lower electron mobility in the GC section covered by the b-P window BL. The narrow b-P window diminishes the Peltier cooling and enhances the detector performance. The proposed device structure and its operation principle promote elevated-temperature GC-FET THz detector responsivity values and other characteristics, especially at the plasmonic resonances.

Dynamic characteristics of terahertz hot-electron graphene FET bolometers: Effect of electron cooling in channel and at side contacts

“…35), using such detectors provides new opportunities for the THz applications. In this regard, GC-FET bolometers proposed recently, 4,8 which exploit the hot-electron bolometric effect reinforced by the plasmonic resonance with the peak responsivity of about (6-7) kV/W deserve attention. Apart from the elevated responsivity, these GC-FET bolometers might demonstrate, as shown above, fairly high operation speed enabling the registration of the THz signals modulated at the modulation frequency of about 20 GHz.…”

“…Since the quality of the h-BN/GC interface supports very high electron mobility (see, for example, Refs. [8][9][10][11] and, therefore, a low electron collision frequency, the plasmonic oscillations damping in the GC-FETs can be markedly weaker than the GC-FETs with black-P x As 1Àx BLs. Due to a relatively narrow emission window, the role of the Peltier cooling is diminished.…”

“…The plasmonic resonances in the gate GC of the devices under consideration can substantially affect the absorption of the impinging radiation and, hence, the detector performance. The recently proposed GC-FET bolometers with the composite BL 8 have reinforced plasmonic resonances. Such a composite BL is made of the h-BN layer with a short narrow-gap black-P x As 1Àx region.…”