Terahertz wave generation and detection in double-graphene layered van der Waals heterostructures

Abstract

We report on the first experimental observation of terahertz emission and detection in a double graphene layered(GL) heterostructure which comprises a thin hexagonal-boron nitride tunnelbarrier layer sandwiched between two separately contacted GLs. Inter-GL population inversion is induced by electrically biasing the structure. Resonant tunneling and negative differential resistance is expected when the two graphene band structures are perfectly aligned. However, in the case of small misalignments we demonstrate that the photon-absorption/emission-assisted non-resonant-and resonant-tunneling causes all excess charges in the n-type GL to recombine with the holes in the p-type GL giving rise to an increased measured dc current. This work highlights a novel strategy for the realization of efficient voltage-tunable terahertz emitters and detectors.

Negative terahertz conductivity and amplification of surface plasmons in graphene–black phosphorus injection laser heterostructures

“…The gapless energy spectrum of graphene layers (GLs) [1,2] enables their use in the interband photodetectors [3][4][5][6] (see also the review articles [7][8][9][10][11] and the references therein) and sources (for example, [11][12][13][14][15][16][17][19][20][21][22][23][24][25][26][27][28] operating in the terahertz (THz) a far-infrared (FIR) spectral ranges. In particular, the optical [12,14,[17][18][19][20][21] and lateral injection pumping of the GLs from the side nand p-contacts (i.e., from the chemically-or electricallydoped regions) [13,16,22,[24][25][26][27] can lead to the interband population inversion and negative dynamic conductivity. This can enable the THz lasing experimentally demonstrated.…”

“…This can enable the THz lasing experimentally demonstrated. The GL-based heterostructure with lateral current injection and the grating providing the distributed feedback exhibits a single-mode lasing at 5.2 THz and a broadband (1 -8 THz) amplified spontaneous emission both at 100 K [24][25][26]. To increase the operating temperature and further enhance the THz gain and lasing radiation intensity, the injection efficiency should be elevated.…”

Terahertz light-emitting graphene-channel transistor toward single-mode lasing

“…To break through these substantial limitations, graphene has attracted attention owing to its gapless and linear energy spectrum and massless Dirac Fermions, giving rise to superior carrier transport properties [27][28][29][30][31]. The latest studies have reported on the potential of relatively simpler multi-layer graphene devices [32,33] to more complex graphene/h-BN heterostructures [34,35] for highly sensitive detection as well as emission of THz radiation [35].…”

Negative Terahertz Conductivity at Vertical Carrier Injection in a Black-Arsenic-Phosphorus–Graphene Heterostructure Integrated With a Light-Emitting Diode

“…The gapless energy spectrum of graphene layers (GLs) [1] supporting the terahertz (THz) and far-infrared (FIR) radiative interband transitions enables the detection, control, and generation of the THz and FIR radiation (see, for example, the review articles [2][3][4][5][6] and the references therein). One of the most interesting potential application of the GLs and the GL-based heterostructures is their use in efficient THz and FIR lasers that were predicted to operate at room temperature and already demonstrated operation at 100 K [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Such lasers can be particularly useful in the spectral range below 5 to 10 THz where the operation of the heterostructure lasers based on A 3 B 5 compounds is hampered by a strong radi-ation absorption by the optical phonons.…”