Effect Of Vertical Electric Field Research Articles

Effect of vertical electric field on the band dispersion and dielectric response of bilayer germanium carbide

In this work, the electronic structure and optical spectra of bilayer GeC and the effects of vertical electric field on its band structure and dielectric response are investigated through ab initio calculation. The electronic structure calculations reveal that bilayer GeC exhibits a direct band gap of 1.55 eV at the K point and the band gap width of bilayer GeC is smaller than that of monolayer GeC. A monotonically reduction of the GeC band gap from 1.55 eV to 0.95 eV has been observed by increasing the electric field from 0 to 1 eV. For parallel polarized light, only the low energy region (E < 3eV) of optical spectrum is influenced by application of vertical electric field. For perpendicular polarized light, the peaks are blue shifted upon application of vertical electric field. The value of static dielectric constant for (E‖x) and (E‖z) increases by increasing the electric field. These results are useful for application of two-dimensional GeC in nanoelectronic and optoelectronic devices.

Effects of vertical electric field and compressive strain on electronic properties of bilayer ZrS2**Project support by the CAS/SAFEA International Partnership Program for Creative Research Teams and the Basic and Frontier Technology Research of Henan (No. 142300410244).

Using first-principles calculations, including Grimme D2 method for van der Waals interactions, we investigate the tuning electronic properties of bilayer zirconium disulfides (ZrS2) subjected to vertical electric field and normal compressive strain. The band gap of ZrS2 bilayer can be flexibly tuned by vertical external electric field. Due to the Stark effect, at critical electric fields about 1.4 V/Å, semiconducting-metallic transition presents. In addition, our results also demonstrated that the compressive strain has an important impact on the electronic properties of ZrS2 bilayer sheet. The widely tunable band gaps confirm possibilities for its applications in electronics and optoelectronics.

Asymmetric Stark shift in an impurity doped dome-shaped quantum dot with wetting layer

The effects of vertical electric field and donor impurity on the electronic properties of the dome-shaped InAs/GaAs quantum dot coupled to its wetting layer were investigated. The dependence of the electron density, energy and Stark shift of the S-, P- and WL-states on the applied electric field was studied with and without impurity. The S- and P-states have no significant qualitative changes in the shape of the wave functions with increasing the electric field, except that they become slightly shifted due to the competition between the field action and the quantum confinement. The wave function of the WL-state is strongly modified in polarized structures. Our results reveal that the Stark shift of electron energies can be fitted with a quadratic dependence on the electric field, the linear and quadratic terms corresponding to the dipole moment and static electron polarizability. Their estimated values reasonable agree with those calculated.

Electric field-induced nonlinearity enhancement in strained semi-spheroid-shaped quantum dots coupled to wetting layer

In this work, the effects of vertical electric field on the electronic and optical properties of strained semi-spheroid-shaped InAs/GaAs quantum dot (QD) coupled to its wetting layer (WL) aimed to enhance the nonlinear optical properties were investigated. The dependence of energy eigenvalues of S- and P- states and intersubband P-to-S transition energy on applied electric field was studied. A ∼∓ߙ10 meV Stark shift in the intersubband P-to-S transition energy was calculated for a semi-spheroid-shaped QD with height of 5 nm and base-length of 20 nm when bias voltage was varied from 0 V to ±0.8V. The dependence of transition dipole moment and linear and nonlinear optical properties of the system on bias voltage was also studied. It was concluded that increasing the bias voltage from -0.8V to +0.8V leads to increase in figure of merit of the system from ∼0.153 to ∼0.198.

Tuning Electronic Structure of Bilayer MoS2 by Vertical Electric Field: A First-Principles Investigation

Interest in the two-dimensional MoS2 material is consistently increasing because of its many potential applications, in particular in the next-generation nanoelectronic devices. By means of density functional theory computations, we systematically examined the effect of vertical electric field on the electronic structure of MoS2 bilayer. The bandgaps of the bilayer MoS2 monotonically decrease with an increasing vertical electric field. The critical electric fields, at which the semiconductor-to-metal transition occurs, are predicted to be in the range of 1.0–1.5 V/A depending on different stacked conformations. Ab initio quantum transport simulations of a dual-gated bilayer MoS2 channel clearly confirm that the vertical electric field continuously manipulates the transmission gap of bilayer MoS2.

Multilayer graphene under vertical electric field

We study the effect of vertical electric field (E-field) on the electronic properties of multilayer graphene. We show that the effective mass, electron velocity, and density-of-state of a bilayer graphene are modified under the E-field. We also study the transformation of the band structure of multilayer graphenes. E-field induces finite (zero) band gap in the even (odd)-layer ABA-stacking graphene. On the other hand, finite band gap is induced in all ABC-stacking graphene. We also identify the optimum E-field to obtain the maximum band gap in the multilayer graphenes. Finally, we compare our results with the experimental results of a field-effect-transistor.

Effect of vertical electric fields on exciton fine structure of GaAs natural quantum dots

The effect of vertical electric fields on the neutral exciton of GaAs “natural” quantum dots is investigated. A Stark effect with a quadratic field dependence up to 2 meV was observed and reveals a displacement of the excitonic wave function. The luminescencequenching limits the applied electric field range. No significative change on the fine structure splitting of the neutral exciton has been observed, suggesting that the lateral potential induced by the vertical electric field is too weak to modify the in-plane anisotropy of the exciton wave function.

Jump of water droplet from a super-hydrophobic film by vertical electric field

The effect of vertical electric fields on the movement of water droplets on a super-hydrophobic film was investigated. A vertical electric field induces a water droplet on a super-hydrophobic to jump up from the surface without splitting itself. Although the voltage required for the droplet jump is still high, it depends on the droplet size, and detailed electrode design may further reduce the voltage.