Terahertz surface emission from layered semiconductor WSe2

Si, Keyu; Huang, Yuanyuan; Zhao, Qiyi; Zhu, Lihua; Zhang, Longhui; Yao, Zehan; Xu, Xinlong

doi:10.1016/j.apsusc.2018.04.117

Cited by 42 publications

(43 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Compared to the other photocurrent electrical detection with electrodes, THz emission spectroscopy is a nondestructive way with more information such as polarization, amplitude, phase, and polarity . THz emission spectroscopy has been used for the photophysical understanding of some advanced materials such as layered materials MoS 2 , WS 2 , WSe 2 , CH 3 NH 3 PbI 3 , and topological insulator . However, these is no evidence yet of high‐order shift current by TPA process involved in THz emission possibly due to low TPA cross‐sections in these materials.…”

Section: Introductionmentioning

confidence: 99%

High‐Order Shift Current Induced Terahertz Emission from Inorganic Cesium Bromine Lead Perovskite Engendered by Two‐Photon Absorption

Huang

et al. 2019

Adv Funct Materials

Self Cite

View full text Add to dashboard Cite

High-order nonlinear optical phenomena are interesting from a fundamental point of view as they reveal intrinsic symmetries of the materials. Potentially they can also be used for practical optoelectronic applications. High-order shift current is one of these phenomena, and yet it has never been detected in experiments, primarily due to the difficulty in conventional contact detection. In this work, the shift current due to the two-photon absorption (TPA) from all-inorganic perovskite CsPbBr 3 is first observed by a contactless and nondestructive terahertz (THz) emission method. The results reveal that the THz emission is dominated by a high-order shift current (fourth-order nonlinear optical effect) with the below-bandgap photon energy of femtosecond laser excitation. The high-order shift current origins from the broken inversion symmetry induced by the dynamic stereochemical activity of the Pb 2+ lone pair. A microscopic TPA-assisted nonlinear optical model is presented to describe the photophysical process of the THz emission. The model matches well with the quadratic pump fluence and angular dependence of the THz emission. This work can not only open a new venue for the all-inorganic perovskite-based nonlinear optoelectronics and THz devices, but also afford a THz technology for the high-order nonlinear effect analysis.

show abstract

Section: Introductionmentioning

confidence: 99%

High‐Order Shift Current Induced Terahertz Emission from Inorganic Cesium Bromine Lead Perovskite Engendered by Two‐Photon Absorption

Huang

et al. 2019

Adv Funct Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…Following photoexcitation, we find relatively slow (time scale ∼ 0.6 ps) out-of-plane photocurrents that are dominant in the ML samples and fast (∼ 50 fs) in-plane photocurrents that are dominant in the BL devices. We ascribe the out-of-plane photocurrent in the ML to drift of photoexcited carriers in the surface electric field [25][26][27][28] and the in-plane photocurrent in the BL to a resonant shift current [29][30][31][32][33]. Finally, the large bandwidth of our experiment allows us to detect oscillations in the THz emission which we attribute to quantum beats between inter-and intra-layer excitonic states in MoSe 2 [34][35][36].…”

mentioning

confidence: 70%

Ultrafast photocurrents in MoSe₂ probed by terahertz spectroscopy

et al. 2021

View full text Add to dashboard Cite

We use the terahertz (THz) emission spectroscopy to study femtosecond photocurrent dynamics in the prototypical 2D semiconductor, transition metal dichalcogenide MoSe2. We identify several distinct mechanisms producing THz radiation in response to an ultrashort (30 fs) optical excitation in a bilayer (BL) and a multilayer (ML) sample. In the ML, the THz radiation is generated at a picosecond timescale by out-of-plane currents due to the drift of photoexcited charge carriers in the surface electric field. The BL emission is generated by an in-plane shift current. Finally, we observe oscillations at about 23 THz in the emission from the BL sample. We attribute the oscillations to quantum beats between two excitonic states with energetic separation of ∼100 meV.

show abstract

“…Что касается нелинейно-оптических механизмов генерации, то в объемном центросимметричном 2H-WSe 2 с пространственной группой маловероятна генерация за счет эффекта оптического выпрямления. В центросимметричных средах нелинейные эффекты второго порядка не проявляются, однако возможен вклад в генерацию ТГц излучения, связанный с возникновением нелинейной поляризации третьего порядка -процесс поверхностного оптического выпрямления [8]:…”

Section: результаты и обсужденияunclassified

“…В нецентросимметричных кристаллах механизм возникновения ТГц-генерации в основном обусловлен вкладом, связанным с возникновением компоненты нелинейной поляризации второго порядка (оптическое выпрямление [3]). В случае центросимметричного кристалла возможен вклад в генерацию ТГц-излучения за счет поверхностного оптического выпрямления -нелинейного эффекта третьего порядка [8]. Диаграмма направленности генерируемого ТГц-излучения, которое возникает за счет эффекта нелинейно-оптического выпрямления, может быть схожа с диаграммой направленности ТГц-излучения, генерируемого в нелинейно-оптических кристаллах ZnTe [9].…”

unclassified

Terahertz generation from surface of the bulk and monolayer tungsten diselenide

Khusyainov

Gorbatova

Buryakov

2020

Rossijskij tehnologičeskij žurnal

View full text Add to dashboard Cite

The study of ultrafast laser interaction with graphene-like materials based on transition metal dichalcogenides attracts most scientific groups. It is connected with potential use of these materials in flexible optoelectronic devices of visible and THz range. In this paper the parameters of generation of terahertz field from the surface of bulk layered crystal and monolayer film of tungsten diselenide are analyzed. Generation of terahertz radiation from the surface of experimental samples was studied by the terahertz time-domain spectroscopy in reflection geometry. Bulk layered crystals of tungsten diselenide were grown by gas transport reactions. Monolayers of tungsten diselenide crystals were grown by chemical vapor deposition on a silicon substrate. The bandwidth of the generated terahertz radiation from the surface of the bulk layered tungsten diselenide crystal was ~ 3.5 THz. For tungsten diselenide monolayer the spectrum bandwidth of the generated THz radiation was ~ 2.5 THz. The peak amplitude of the generated terahertz field for both samples was at a frequency of ~ 1 THz. Research of the influence of the angle of rotation of a polarization plane of optical femtosecond pump on peak-to-peak amplitude of the generated terahertz field from the surface of investigated samples was carried out. Symmetry analysis of the azimuthal dependence of THz radiation made it possible to separate the mechanisms of THz radiation and evaluate their contribution. The analysis results confirm that the only possible contribution to the generation of terahertz radiation in a tungsten diselenide monolayer crystal is the second order nonlinear optical effect – optical rectification. One of the contributions to the generation of tungsten diselenide is a nonlinear-optical effect of the third order – surface optical rectification.

show abstract

Terahertz surface emission from layered semiconductor WSe2

Cited by 42 publications

References 58 publications

High‐Order Shift Current Induced Terahertz Emission from Inorganic Cesium Bromine Lead Perovskite Engendered by Two‐Photon Absorption

High‐Order Shift Current Induced Terahertz Emission from Inorganic Cesium Bromine Lead Perovskite Engendered by Two‐Photon Absorption

Ultrafast photocurrents in MoSe₂ probed by terahertz spectroscopy

Terahertz generation from surface of the bulk and monolayer tungsten diselenide

Contact Info

Product

Resources

About

Terahertz surface emission from layered semiconductor WSe2

Cited by 42 publications

References 58 publications

High‐Order Shift Current Induced Terahertz Emission from Inorganic Cesium Bromine Lead Perovskite Engendered by Two‐Photon Absorption

High‐Order Shift Current Induced Terahertz Emission from Inorganic Cesium Bromine Lead Perovskite Engendered by Two‐Photon Absorption

Ultrafast photocurrents in MoSe2 probed by terahertz spectroscopy

Terahertz generation from surface of the bulk and monolayer tungsten diselenide

Contact Info

Product

Resources

About

Ultrafast photocurrents in MoSe₂ probed by terahertz spectroscopy