Customized modulation on plasma uniformity by non-uniform magnetic field in capacitively coupled plasma

A two-dimensional fluid model based on COMSOL Multiphysics is developed to investigate the modulation of static magnetic field on plasma homogeneity in a capacitively coupled plasma(CCP)chamber. To generate a static magnetic field, direct current is applied to a circular coil located at the top of the chamber. By adjusting the magnetic field's configuration, which is done by altering the coil current and position, both the plasma uniformity and density can be significantly modulated. In the absence of the magnetic field, the plasma density exhibits an inhomogeneous distribution characterized by higher values at the plasma edge and lower values at the center. The introduction of a magnetic field generated by coils results in a significant increase in electron density near the coils. Furthermore, an increase in the sets of coils improves the uniformity of the plasma. By flexibly adjusting the positions of the coils and the applied current,a substantial enhancement in overall uniformity can be achieved. These findings demonstrate the feasibility of using this method for achieving uniform plasma densities in industrial applications.

New Approaches in Frequency Conversion of Laser Radiation in Plasma Plumes

Recent studies of plasma harmonic generation are reviewed. We show the advances of this technique for generation of coherent ultrashort pulses in the extreme ultraviolet range. Among the achievements highlighted in this review are the comparative experimental and theoretical studies of high-order harmonic generation in silver plasma, isolated subfemtosecond pulse generation in Mn plasma ablation, stable generation of high-order harmonics of femtosecond laser radiation from laser produced plasma plumes at 1 kHz pulse repetition rate, and high-order harmonic generation in fullerenes using few- and multi-cycle pulses of different wavelengths. We show that new developments of plasma harmonic studies can lead to the creation of an attractive field of laser ablation induced high-order harmonic generation spectroscopy.

Study of doping uniformity of a 200 kV ion implanter by RBS and sheet resistance measurements

The ion implantation uniformity is of vital importance for an ion implanter.In this paper,we report the,uniformity measurement for a large current ion implanter(LC-16 type) by implanting of 190-keV Ar ions into Si to 3×1016 atoms/cm2,followed by Rutherford backscattering spectroscopy(RBS) and sheet resistance measurement providing quantitative information on spatial distribution of dopants.The implant doses obtained from RBS at selected points of the sample give a spatial uniformity of <5%,which are confirmed by the sheet resistance measurement.While sheet resistance is an indirect method for dose evaluation of ion-implanted samples,RBS provides a competent technique for calibration of the ion implantation system.And both measurements show that good uniformity can be achieved for the ion implanter by tuning of the scanning process.

Multilayer GaAs-Based Heterostructures with Holographic Concentrator for Solar Cells

The present paper studies the issue of forming a diffraction concentrator in the form of relief diffraction gratings. The possibility of their application for solar energy systems based on GaAs heterostructures has been studied. It was shown that the use of diffractive and holographic concentrators proves to be very effective, since they provide for the increased radiant flux onto sensitive surface of the solar cell, whereas no automatic solar tracker is required. This will create novel approaches for a wide range application of gallium arsenide solar cells.

Synergistical heterointerface engineering of Fe-Se nanocomposite for high-performance sodium-ion hybrid capacitors

As environmentally benign and high-efficiency energy storage devices,sodium-ion capacitors(SICs),which combine the merits of batteries and supercapacitors,are considered to have potentially high energy/power densities and long lifespan.However,the lack of high-rate anodes that can match the high-power-density cathode hinders the commercial application of SICs.In this work,heterostructured Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite is pre-pared by chemical vapor deposition(CVD)method and investigated as the anode for SICs.Through heterointerface manipulation,Fe/FeSe_(2)/Fe_(3)Se_(4)demonstrates better sodium ion storage performances than the pure FeSe_(2)and FeSe_(2)/Fe_(3)Se_(4).It can deliver a specific capacity of 484.8 mAh·g^(-1)after 100 cycles at 0.5 A·g^(-1),as well as a good capacity retention.The excellent performance of Fe/FeSe_(2)/Fe_(3)Se_(4)nanocomposite can be ascribed to the synergistic effect of the heterointerface engineered components,where FeSe_(2)and Fe_(3)Se_(4) are responsible for offering a high capacity and metallic Fe can server as mini-current collectors,effec-tively accelerating the electron and charge transfer behavior.Meanwhile,the heterointerface significantly facilitates the sodium ion fast transport,and retards the structural variation during cycling.FeSe-1000//activated carbon(AC)SIC affords a high energy density of 112 Wh·kg^(-1)at 107.5 W·kg^(-1),its power density can achieve 10,750 W·kg^(-1)with remained energy density of 44.2 Wh·kg^(-1),as well as an outstanding cycling stability,demonstrating this effective heterointerface engineered anode strategy for high-performance SICs.