Broadband ultra-high transmission of terahertz radiation through monolayer MoS2

Abstract

In this study, terahertz (THz) absorption and transmission of monolayer MoS 2 was calculated under different carrier concentrations. Results showed that the THz absorption of monolayer MoS 2 is very small even under high carrier concentrations and large incident angle. Equivalent loss of the THz absorption is the total sum of reflection and absorption that is one to three grades lower than that of graphene.The monolayer MoS 2 transmission is much larger than that of the traditional GaAs and InAs two-dimensional electron gas. The fieldeffect tubular structure formed by the monolayer MoS 2 -insulationlayer-graphene is investigated. In this structure the THz absorption of graphene to reach saturation under low voltage. Meantime, the maximum THz absorption of monolayer MoS 2 was limited to approximately 5%. Thus, monolayer MoS 2 is a kind of ideal THz Transparent Electrodes. 1 Transparent electrode has important prospective applications in the fields of photodetectors, light-emitting diodes (LEDs), vertical cavity surface emitting lasers (VCSELs), and solar cells, et al [1, 2]. As a novel two-dimensional (2-D) material, graphene has high conductivity and very high light transmission within the range of medium infrared and visible light frequency [2-4].Thus, it is regarded as an ideal transparent electrode material. However, the plasmon of graphene exhibits very high terahertz (THz) absorption when the carrier concentration of graphene is high within the THz or far-infrared frequency range [5][6][7][8][9][10][11][12][13][14]. Therefore, graphene with high carrier concentration in THz frequency range is regarded as an absorption medium instead of a transparent electrode.The frequency of the THz range is mainly the spectrum within 0.1-10 THz. Given its special properties, the spectrum of the THz range has broad applications in communication, medical imaging, radar detection, nondestructive tests, and so on [15,16]. The transparent electrode within the THz frequency range has important prospective applications in THz detectors, modulators, VCSELs, and phase shifters [5][6][7][15][16][17][18][19][20][21][22]. Numerous THz transparent electrodes have been suggested, including two-dimensional electron gas (2DEG), ion-gel, two-dimensional arrays of metallic square holes, graphene with low carrier density, and indium-tin-oxide (ITO) nanomaterials. However, Broadband ultra high transmission THz transparent electrodes is still very desirable.Recently, another 2-D material, namely, monolayer MoS 2 , has attracted much research attention. monolayer MoS 2 has high mobility (∼410 cm 2 V −1 s −1 ) and excellent mechanical properties [23][24][25][26][27][28][29][30][31][32][33][34]. However, its optical property is not the same as that of graphene. The monolayer MoS 2 band gap is not zero, which has a high absorption within the visible-light frequency range.This material can be used as a high-efficiency photoelectric detector material instead of an ideal transparent electrode material within the visible light frequency [23-31, 35, 36...

Recent Progress on Irradiation-Induced Defect Engineering of Two-Dimensional 2H-MoS2 Few Layers

“…However, there was no report on terahertz damage on MoS 2 . Theoretical simulations indicated that the THz absorption of mono-layer MoS 2 was very low and the maximum THz absorption of mono-layer MoS 2 was approximately 5% [151]. The sum of reflection and absorption losses of mono-layer MoS 2 was lower than that of graphene by one to three orders of magnitude.…”

Noncollinearity-modulated Electronic Properties of Monolayer CrI3

“…1,29,30 The carrier concentration on the order of 10 12 cm −2 in MoS 2 has been reported 31 and it can be increased to be an order of magnitude larger via doping or gating. 31,32 The estimated carrier concentration is 2 or 3 orders of magnitude smaller than the density of valence electrons (2.6 × 10 16 cm −2 ) in the monolayer CrI 3 such that the electronic structure can hardly be influenced by the occupation of these carrier. This fact justifies our estimation of carrier concentration based on the calculated DOS of neutral systems.…”

Broadband electrically tunable VO2‑Metamaterial terahertz switch with suppressed reflection

“…However, when the polarization and electrode arms are parallel, the transmission is strongly suppressed. This limitation could be eliminated by the introduction of a DC conductive (but THz transparent) material for the electrode, such as MoS 2 . This would allow the device to operate under large angles of incidence as shown and would also make the response independent of azimuthal polarization angle.…”

“…This limitation could be eliminated by the introduction of a DC conductive (but THz transparent) material for the electrode, such as MoS 2 . 47,48 This would allow the device to operate under large angles of incidence as shown and would also make the response independent of azimuthal polarization angle. fairly frequency independent from THz to infrared.…”