Pressure-induced K-Λ crossing in monolayer WSe2.

@article{Ye2016PressureinducedKC,
  title={Pressure-induced K-$\Lambda$ crossing in monolayer WSe2.},
  author={Yanxia Ye and Xiuming Dou and Kun Ding and De-sheng Jiang and Fuhua Yang and Baoquan Sun},
  journal={Nanoscale},
  year={2016},
  volume={8 20},
  pages={
          10843-8
        }
}
The energy band structures and related room temperature exciton transitions of monolayer and bilayer tungsten diselenide (WSe2) are investigated using photoluminescence (PL) spectra under hydrostatic pressure up to 5.42 GPa. For monolayer WSe2, it is found that the conduction band Λ valley is 70 ± 30 meV higher than the K valley at zero pressure, and the K-Λ valley crossover happens at a pressure of approximately 2.25 GPa. The PL peak of exciton related to the direct K-K interband transition in… 
View on PubMed
rsc.org
24 Citations
Background Citations
1

Figures from this paper

24 Citations

Citation Type

Citation Type

Pressure-Induced Photoluminescence Adjustment and Lattice Disorder in Monolayer WSe2
Pressure engineering is considered as a novel strategy to modulate the properties of transition metal dichalcogenide materials. Here, through photoluminescence (PL) and Raman measurements, we…
Pressure-Dependent Light Emission of Charged and Neutral Excitons in Monolayer MoSe2.
TLDR
Under quasi-hydrostatic compressive strain, pressure-tuned photon emission of trions and excitons in monolayer MoSe2 via a diamond anvil cell (DAC) through photoluminescence measurements and theoretical calculations is reported.
Tuning the Direct and Indirect Excitonic Transitions of h-BN by Hydrostatic Pressure
TLDR
The experiments corroborate the theoretical predictions and indicate an enhancement of the indirect nature of the bulk hexagonal boron nitride crystal under hydrostatic pressure.
On the impact of the stress situation on the optical properties of $WSe_2$ monolayers under high pressure
We have studied the optical properties of $WSe_2$ monolayers (ML) by means of photoluminescence (PL), PL excitation (PLE) and Raman scattering spectroscopy at room temperature and as a function of…
Using strain to alter the energy bands of the monolayer MoSe2: A systematic study covering both tensile and compressive states
Anomalous Pressure Characteristics of Defects in Hexagonal Boron Nitride Flakes.
TLDR
Density functional theory calculations indicate the existence of competition between the intralayer and interlayer interaction contributions, which leads to the different pressure-dependent behaviors of the PL peak shift.
Enhanced exciton emission behavior and tunable band gap of ternary W(SxSe1-x)2 monolayer: temperature dependent optical evidence and first-principles calculations.
TLDR
It is demonstrated that exciton emission behavior of single layer W(SxSe1-x)2 nanosheets (0 ≤ x ≤ 1) can be remarkably tuned by changing the sulfur content, and can enable spectral tunability for potential optoelectronic applications.
Coupling-Assisted Renormalization of Excitons and Vibrations in Compressed MoSe2-WSe2 Heterostructure
Vertical heterostructures (HSs) constructed with two-dimensional (2D) materials is expected to generate fascinating properties due to interlayer coupling between neighboring layers. However,…
Strain-Modulated Interlayer Charge and Energy Transfers in MoS2/WS2 Heterobilayer
Excitonic properties in 2D heterobilayers are closely governed by charge transfer (CT) and excitonic energy transfer (ET) at van der Waals interfaces. Various means have been employed to modulate the…
Effects of composition and temperature on the exciton emission behaviors of Mo(SxSe1-x)2 monolayer: Experiment and theory.
TLDR
The controllable synthesis of monolayer Mo(S$x$Se$_{1-x}$)$_{2}$ nanosheets by one-step chemical vapor deposition (CVD) method and systematical investigation on the exciton emission characteristics based on the temperature-dependent photoluminescence spectroscopy (PL) experiments show results consistent with the theoretical results calculated by the density function theory (DFT).
...
1
2
3
...

References

SHOWING 1-10 OF 59 REFERENCES
Tuning and identification of interband transitions in monolayer and bilayer molybdenum disulfide using hydrostatic pressure.
TLDR
It is demonstrated that a direct K-K to an indirect Λ-K interband transition in bilayer MoS2 can be optically detected by tuning the hydrostatic pressure.
Strain-induced direct–indirect bandgap transition and phonon modulation in monolayer WS2
In situ strain photoluminescence (PL) and Raman spectroscopy have been employed to exploit the evolutions of the electronic band structure and lattice vibrational responses of chemical vapor…
Pressure-dependent optical and vibrational properties of monolayer molybdenum disulfide.
TLDR
The results present an important advance toward controlling the band structure and optoelectronic properties of monolayer MoS2 via pressure, which has vital implications for enhanced device applications.
Strain-induced indirect to direct bandgap transition in multilayer WSe2.
TLDR
This work experimentally demonstrates a drastic enhancement in PL intensity for multilayer WSe2 (2-4 layers) under uniaxial tensile strain of up to 2%.
Electron and hole mobilities in single-layer WSe2.
TLDR
Polymer electrolytes allow the charge carrier densities to be modulated to very high values, allowing the observation of both the electron- and the hole-doped regimes, and ohmic contacts formed at low temperatures allow us to study the temperature dependence of electron and hole mobilities.
Origin of indirect optical transitions in few-layer MoS2, WS2, and WSe2.
TLDR
This work investigates the conduction band valley structure in few-layer MX2 by examining the temperature-dependent shift of indirect exciton photoluminescence peak and identifies the origin of the indirect emission and concurrently determine the relative energy of these valleys.
Anomalous Raman spectra and thickness-dependent electronic properties of WSe2
Typical Raman spectra of transition metal dichalcogenides (TMDs) display two prominent peaks, E2g and A1g, that are well separated from each other. We find that these modes are degenerate in bulk…
Probing Critical Point Energies of Transition Metal Dichalcogenides: Surprising Indirect Gap of Single Layer WSe2.
TLDR
Detailed quasi-particle electronic structures in transition metal dichalcogenides are revealed, including the quasi- particle gaps, critical point energy locations, and their origins in the Brillouin zones by using a comprehensive form of scanning tunneling spectroscopy.
Electrical control of neutral and charged excitons in a monolayer semiconductor.
TLDR
This work reports the unambiguous observation and electrostatic tunability of charging effects in positively charged, neutral and negatively charged excitons in field-effect transistors via photoluminescence and finds the charging energies for X(+) and X(-) to be nearly identical implying the same effective mass for electrons and holes.
Influence of pressure on exciton states and interband optical transitions in wurtzite InGaN/GaN coupled quantum dot nanowire heterostructures with polarization and dielectric mismatch
Considering the hydrostatic pressure, the spontaneous and piezoelectric polarization, the dielectric mismatch, and 3D confinement of the electron and hole, the exciton states and interband optical…
...
1
2
3
4
5
...