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

Abstract

Abstract:A distributed feedback dual-gate graphenechannel field-effect transistor (DFB-DG-GFET) was fabricated as a current-injection terahertz (THz) light-emitting laser transistor. We observed a broadband emission in a 1-7.6-THz range with a maximum radiation power of ~10 μW as well as a single-mode emission at 5.2 THz with a radiation power of ~0.1 μW both at 100 K when the carrier injection stays between the lower cutoff and upper cutoff threshold levels. The device also exhibited peculiar nonlinear threshold-like behavior with respect to the current-injection level. The LED-like broadband emission is interpreted as an amplified spontaneous THz emission being transcended to a single-mode lasing. Design constraints on waveguide structures for better THz photon field confinement with higher gain overlapping as well as DFB cavity structures with higher Q factors are also addressed towards intense, single-mode continuous wave THz lasing at room temperature.

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

“…Using the substrates providing weaker energy and momentum carrier relaxation in the GL (instead of hBN considered above, one can achieve a stronger negative dynamic conductivity and higher amplification amplification of the plasmonic modes at a weaker injection. The plasmonic lasing can be enabled by the plasmon reflection from the end faces and by the realization of the distributed feedback using the highly conducting sawtooth (serrated) side contacts [26].…”

“…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.…”

Real-space-transfer mechanism of negative differential conductivity in gated graphene-phosphorene hybrid structures: Phenomenological heating model

“…Unique properties of Graphene (G) [1] and recent advances in technology of van der Waals materials [2,3] present an excellent opportunity for developing effective electronic and optoelectronic devices [3][4][5][6][7][8][9][10][11][12][13][14][15]. Combining the G-layers with the gapless energy spectrum and enhanced electron (and hole) mobility and a few-layer black phosphorus layer or phosphorene (P) [16][17][18][19][20][21][22][23] exhibiting the flexibility of the band structure, open up remarkable prospects for the creation of novel devices, in particular, photodetectors [24].…”

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.…”