A novel power supply system that directly couples pulsed high voltage (HV) pulses and pulsed 13.56 MHz radio frequency (rf) has been developed for plasma processes. In this system, the sample holder is connected to both the rf generator and HV modulator. The coupling circuit in the hybrid system is composed of individual matching units, low pass filters, and voltage clamping units. This ensures the safe operation of the rf system even when the HV is on. The PSPICE software is utilized to optimize the design of circuits. The system can be operated in two modes. The pulsed rf discharge may serve as either the seed plasma source for glow discharge or high-density plasma source for plasma immersion ion implantation (PIII). The pulsed high-voltage glow discharge is induced when a rf pulse with a short duration or a larger time interval between the rf and HV pulses is used. Conventional PIII can also be achieved. Experiments conducted on the new system confirm steady and safe operation.
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http://dx.doi.org/10.1063/1.2906220 | DOI Listing |
Heliyon
December 2024
Laser and Plasma Research Institute, Shahid Beheshti University, Tehran, 1983969411, Iran.
In this article, the propagation of high-frequency (HF) plane electromagnetic waves through the lower ionosphere is numerically investigated using the real geometry of the Earth's magnetic field in the northern hemisphere. For this purpose, the profiles of electron density and the collision frequency in the layers of the lower ionosphere (D- and E-region) are considered using the reported experimental data for day and night. The reflection, transmission, and absorption coefficients of HF radio waves in the frequency range of 3 to 30 MHz are calculated in the ionosphere plasma.
View Article and Find Full Text PDFiScience
November 2024
School of Electronic Information Engineering, Inner Mongolia University, Hohhot 010021, China.
The van der Waals thiophosphate GaPS presents additional opportunities for gallium-based semiconductors, but limited research on phonon interactions has hindered optimization on thermal properties. This research undertakes a comprehensive investigation into the anharmonic phonon scattering within GaPS. The findings reveal pronounced anharmonic scattering, with both cubic and quartic phonon scatterings significantly influencing phonon redshift and broadening.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Graphic Arts and Photophysics, Faculty of Chemical Technology, University of Pardubice, Studentská 573, Pardubice, 532 10, Czech Republic.
Radio frequency magnetron co-sputtering method employing GeTe and Sc targets was exploited for the deposition of Sc doped GeTe thin films. Different characterization techniques (scanning electron microscopy with energy-dispersive X-ray analysis, X-ray diffraction, atomic force microscopy, sheet resistance temperature-dependent measurements, variable angle spectroscopic ellipsometry, and laser ablation time-of-flight mass spectrometry) were used to evaluate the properties of as-deposited (amorphous) and annealed (crystalline) Ge-Te-Sc thin films. Prepared amorphous thin films have GeTe, GeTeSc, GeTeSc, GeTeSc and GeTeSc chemical composition.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Departement de Physique Theorique, Universite de Geneve, 24 quai Ernest Ansermet, 1211 Geneve 4, Switzerland.
Heliyon
November 2024
Faculty of Physics, Shahrood University of Technology, 3619995161, Shahrood, Iran.
This study evaluates the deposition of diamond-like carbon (DLC) films with copper impurities on a glass substrate using simultaneous direct current (DC) and radio frequency (RF) magnetron sputtering. The structural, optical, electrical, and mechanical properties, as well as the surface topography of the films, were investigated under various DC power levels using Raman spectroscopy, ellipsometry, UV-VIS, I-V measurements, nanoindentation, AFM, and FESEM. Results indicate that increasing the DC power to the graphite target from 60 to 120 , while maintaining a constant 10 of RF power to the copper target, enhances the optical absorption coefficient of the films and increases the optical bandgap from 0.
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