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Plasma polymerized fluorocarbon (FC) films have been deposited on silicon substrates from dielectric barrier discharge (DBD) plasma of C4F8 at room temperature under a pressure of 25~125 Pa. The effects of the discharge pressure and frequency of power supply on the films have been systematically investigated. FC films with a less cross linked structure may be formed at a relatively high pressure. Increase in the frequency of power supply leads to a significant increase in the deposition rate. Static contact angle measurements show that deposited FC films have a stable, hydrophobic surface property. All deposited films show smooth surfaces with an atomic surface roughness. The relationship between plasma parameters and the properties of the deposited FC films are discussed.

Here we presented a simple approach to fabricate the microstructures of InP by electrochemical etching. Microrods were formed while InP etched in 7 M HCl solutions for 30 s, and microtips were obtained while InP etched for 120 s. In addition, with increasing applied potential the surface of the microrods became smoother. The formation mechanism was also discussed in this article.

Vortex patterns of dust particles have been observed in a magnetized dusty plasma system. The formation mechanism of two-dimensional (2D) vortex patterns has been investigated by analysing the forces acting on dust particles and molecular dynamics (MD) simulations in a 2D confined magnetized dusty plasma. It has been found that with a weak confining electric field and a strong magnetic field, the particles' trajectories will form a vortex shape. The simulation results agree with our experimental observations. In our experiments, vortex patterns can be induced via circular rotation of particles by changing the rf (radio-frequency) power in a magnetized dusty plasma.

Atomic force microscopy is used to estimate and compare the surface morphology of hydrogenated and hydrogen-free diamond-like carbon (DLC) films. The films were prepared by using DC magnetron sputtering of a graphite target, pulsed cathodic carbon arcs, electron cyclotron resonance (ECR), plasma source ion implantation and dielectric barrier discharge (DBD). The difference in the surface structure is presented for each method of deposition. The influences of various discharge parameters on the film surface properties are discussed based upon the experimental results. The coalescence process via the diffusion of adsorbed carbon species is responsible for the formation of hydrogen-free DLC films with rough surfaces. The films with surface roughness at an atomic level can be deposited by energetic ion impacts in a highly ionized carbon plasma. The dangling bonds created by atomic hydrogen lead to the uniform growth of hydrocarbon species at the a-C:H film surfaces of the ECR or DBD plasmas.

The structure and phase transition of a two-dimensional (2D) dusty plasma have been investigated in detail by molecular dynamics simulation. Pair correlation function, static structure factor, mean square displacement and bond angle correlation function have been calculated to characterize the structural properties. The variation of internal energy, shear modulus, particle trajectories and structural properties with temperature has been monitored to study the phase transition of the 2D dusty plasma system. The simulation results are in favour of a two-step continuous transition for this kind of plasma.

Collective motion modes existing in a two-dimensional Yukawa system are investigated by molecular dynamics simulation. The dispersion relations of transverse and longitudinal lattice waves obtained for hexagonal lattice are in agreement with the theoretical results. The negative dispersion of the parallel longitudinal wave is demonstrated by the simulation, and is explained by a physical model.

Like the spin in spintronics, the valley index in graphene can be viewed as a new carrier of information, which is useful for designing modern electronic devices. Recently, we have applied the concept of valleytronics to photonic graphene, revealed valley-dependent beam splitting effect and realized pseudomagnetic field. The pseudomagnetic field enables a novel manipulation of photons. In this paper, the photonic analogy of valley Hall effect in uniaxially distorted photonic graphene is investigated. It is found that photons in two valleys are subjected to pseudomagnetic fields that are equal in strength but opposite in sign. With the increasing of distortion, the valley Hall effect becomes stronger. In addition, it is found that the photonic valley Hall effect can still be maintained under the influence of loss, although the beam intensity decreases. The photonic analogy of valley Hall effect induced by pseudomagnetic field in uniaxially distorted photonic graphene may be very useful for controlling the flow of light in future valley-polarized devices.

A Monte Carlo simulation technique has been used to model the electron transport behavior, especially the electron density and energy distributions under the influence of a mirror magnetic field and a uniform electric field in a positive column of helium direct current (DC) gas discharge. Graphs showing the electron density and energy distributions, and the percentage of electrons that reach the wall and the end of the positive column are presented. The results indicate that the mirror magnetic field can control the electron transport behavior in the positive column which are in good agreement with experimental results.

A two-dimensional dusty plasma lattice in an rf discharge was observed. The structural and dynamical properties were analysed by computing pair correlation function, static structure factor, bond-orientational correlation function and mean square displacement. The bond-orientational correlation function was found to fit into the law of r-0.25, and the mean square displacement experienced ``ballistic'', ``subdiffusive'' and ``diffusive'' regimes, both of which together with the other parameters indicate that the two-dimensional dusty plasma stayed at a state between liquid and solid.

Recently, Chan and his collaborators reported that a crossing point of bands can be achieved at the Brillouin zone center in two-dimensional (2D) dielectric photonic crystals (PhCs) by accidental degeneracy of modes. At the crossing point, the accidental threefold degeneracy of modes generates a Dirac cone and an additional flat band (longitudinal mode) intersecting the Dirac cone. This is different from that of the Dirac point at the corner of the hexagonal Brillouin zone in which only Dirac cone exists. As a result, the crossing point at the Brillouin zone center is called a Dirac-like point. If the accidental degeneracy occurs by a monopole mode and two dipolar modes, the dielectric PhCs can be mapped to a zero-refractive-index system in which the effective permittivity and permeability are zero at the Dirac-like point from the effective medium theory. According to the Maxwell equations, if the permittivity and permeability are zero, the optical longitudinal modes can exist, in additional to the well-known transverse modes. The additional flat band at the Dirac-like point is closely connected with the longitudinal mode. For a homogeneous zero-index material (ZIM), the flat band is dispersionless and the longitudinal mode cannot couple with the external light. But in a finite-sized PhC, there is always some spatial dispersion, so the flat band is not perfectly dispersionless when it is away from the zone center. Therefore, if the wave source is a Gaussian beam with non-zero k-parallel components, the longitudinal mode can be excited. And the effective wavelength of ZIM is extremely large, leading to many scattering properties. However, in a PhC which behaves as if it had a zero refractive index, it is very interesting to show how the longitudinal mode influences the wave propagations in the PhC when the longitudinal mode is excited. In this paper, the effect of longitudinal mode on the transmission properties near the Dirac-like point of PhCs is investigated by numerical simulation. The alumina dielectric rods can be moved randomly in the structure to result in the disorder of the structure. Our results show that the transmission properties at the Dirac-like point are very different from those near the Dirac-like point, when the longitudinal mode is excited. At the Dirac-like point, the transmittance decreases with increasing disorder, as a result of the influence of the longitudinal mode, which is similar to the one in the pass band. Above the Dirac-like point without the disturbance of longitudinal mode, the transmittance is insensitive to the disorder in the structure, so that the structure may mimic a near-zero index materials and have a large effective wavelength. These results may further improve the understanding about the optical longitudinal mode and the zero refractive material.