K. Pyszniak

Arc discharge ion source for europium and other refractory metals implantation

The best method for the impurity doping to the host material is the ion implantation. Due to high melting point of the rare earth standard metal ion sources are useless. One of the solution is to use chemical compounds of rare earths characterized by low melting point. In this paper we describe the novel design of the ion source suitable for refractory metal (e.g., rare earths) ion implantation. The dependencies of Eu(+) current on cathode and arc currents as well as on hydrogen flow are presented. Europium (III) chloride as the source of the europium atoms was used. Europium ions were produced during collisions of evaporated and decomposed EuCl(3) molecules with fast electrons. The typical current of the europium ion beam extracted from the ion source was 25 microA for the extraction voltage of 25 kV. The ion source works without maintenance breaks for approximately 50 h, which enables high dose implantation. The presented ion source needs neither advanced high power supplies nor high vacuum regime.

InP nanocrystals on silicon for optoelectronic applications

One of the solutions enabling performance progress, which can overcome the downsizing limit in silicon technology, is the integration of different functional optoelectronic devices within a single chip. Silicon with its indirect band gap has poor optical properties, which is its main drawback. Therefore, a different material has to be used for the on-chip optical interconnections, e.g. a direct band gap III-V compound semiconductor material. In the paper we present the synthesis of single crystalline InP nanodots (NDs) on silicon using combined ion implantation and millisecond flash lamp annealing techniques. The optical and microstructural investigations reveal the growth of high-quality (100)-oriented InP nanocrystals. The current-voltage measurements confirm the formation of an n-p heterojunction between the InP NDs and silicon. The main advantage of our method is its integration with large-scale silicon technology, which allows applying it for Si-based optoelectronic devices.

Optical and microstructural properties of self-assembled InAs quantum structures in silicon

The InAs quantum structures were formed in silicon by sequential ion implantation and subsequent thermal annealing. Two kinds of crystalline InAs nanostructures were successfully synthesized: nanodots (NDs) and nanopyramids (NPs). The peaks at 215 and 235 cm−1, corresponding to the transverse optical (TO) and longitudinal optical (LO) InAs single-phonon modes, respectively, are clearly visible in the Raman spectra. Moreover, the PL band at around 1.3 µm, due to light emission from InAs NDs with an average diameter 7±2 nm, was observed. The InAs NPs were found only in samples annealed for 20 ms at temperatures ranging from 1000 up to 1200°C. The crystallinity and pyramidal shape of InAs quantum structures were confirmed by HRTEM and XRD techniques. The average size of the NPs is 50 nm base and 50 nm height, and they are oriented parallel to the Si (001) planes. The lattice parameter of the NPs increases from 6.051 to 6.055 Å with the annealing temperature increasing from 1100 to 1200°C, due to lattice relaxation. Energy dispersive spectroscopy (EDS) shows almost stoichiometric composition of the InAs NPs.

Simulations of ionization in a hot cavity surface ion source

A new numerical Monte Carlo method based model of a hot cavity surface ionization ion source is presented in this paper. The model, intended to support the studies on ionization phenomena in a widely used class of ion sources, takes into account geometry of the ion source and extraction system, ionizer temperature and other features. The results of ion source efficiency calculations for various configurations of the extraction field are reviewed. The dominant role of the ionizer region near the extraction opening is described. Simulated dependences of ionization efficiency on the working parameters like ionizer length and temperature, ionization potential of the substance, and extraction voltage are discussed. A good agreement of the experimental data (e.g., influence of ionizer temperature, current-voltage curve) and the predictions of the model is found. It is also shown that the contribution to the ionization yield from impact of thermionic electrons accelerated by the extraction field may be significant, especially for the substances of small surface ionization coefficient. The simulation results are compared to the predictions of different theoretical models of the ion source--the obtained simulation data are in accordance both with a well-known Kirchner formula and the so called spherical ionizer model.

Plasma ion source with hollow cathode

Abstract The paper describes a plasma ion source for ionization of low-volatile elements of a high ionization potential. The source is characterized by a high operation temperature and relatively effective ionization. Plasma in a closed volume of the hollow cathode is produced by thermoemission electrons and ionized atoms dosed to the source or diffused from the walls of heated cathode. The construction of the source makes its operation possible in electromagnetic isotope separators on-line, e.g. on a beam of highly energetic protons of YASNAPP facility (Nucl. Instrum. Methods B70 (1992) 62).

Multiple ionization in plasma ion source of electromagnetic isotope separator

Abstract This paper discusses the ion beam production of multiply charged ions in the electromagnetic isotope separator. The paper is divided into five sections, in which the ion source construction is described and a phenomenological model describing the formation of multiply charged ion beams is proposed. An analysis of the experiment data within the framework of the proposed model has been carried out, and as a result of this the rate constants for the ion production and destruction processes have been determined.

Production of Molybdenum and Tantalum Ion Beams using CCl2F2

Conformal Invariance and Conserved Quantities for Lagrange Equation of Thin Elastic Rod Peng Wanga,∗, Hui-Rong Feng and Zhi-Mei Lou School of Civil Engineering and Architecture, University of Jinan, Jinan, Shangdong, 250022, P.R. China College of Transportation and Civil Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian, 350002, P.R. China Department of Physics, Shaoxing University, Shaoxing, Zhejiang, 312000, P.R. China

Negative ion beams from a plasma type source with additional surface ionization

The universal variant of the ion source is now operational in the mass separator of the Institute of Physics, M Curie-Sklodowska University. The source produces a wide range of ion beams, both negative and positive. Special emphasis has been given to the ionization processes taking place in the device. The source design and selected examples of its characteristics are given.