The results were analyzed and systematized and approaches were elaborated to nondestructive monitoring of the surface ion modification. The damage profiles were simulated for metals (Cu, Al, Mo, stainless steel) being irradiated by different ions (H+/D+, Ar+, metal ions) within wide energy range (E=1 keV - 1 MeV). Optical properties of mono-, polycrystalline and amorphous materials were studied by means of angular (wavelength λ=632.8 nm) and spectral ellipsometry (probing photons energy range 0.05-5 eV). The surface of metals were also probed by Auger electron spectroscopy, scanning electron microscopy and atomic force microscopy. As a result of IR ellipsometric studies it has been revealed that treatment of the polycrystalline Ti surface by the mixed Ti+ and C+ ion beam caused much stronger changes of its subsurface optical properties that treatment of polycrystalline Mo by the same ion beam, because the bombarding ions (Ti+) have an affinity with Ti surface atoms.
The treatment resulted in formation on Ti surface disordered layer with non-Drude-like behavior of the optical properties. Irradiation of Mo surface by the same ion beam induced the changes of free electron scattering mechanism while optical conductivity remains Drude-like.
An electronic system based on a novel high-speed massive video memory array using an optical fiber clock distribution network has been investigated for the generation of random patterns for testing high-resolution color video monitors with screen sizes in the realm of 4096 by 4096 pixels. For frame rates in the range of 30 to 100 per second with 256 (28) to 4096 (212) intensity levels for each primary color the speed requirement amounts to 1.21x1010 to 6.04x1010 bits per second. The massive memory makes use of high-speed MSM photodetectors, optical receiver amplifiers and gallium arsenide charged coupled devices which are integrated on GaAs chips. These chips are assembled into 16 planes of multi-chip modules with 32 GaAs chips per plane. Only GaAs CCDs have been found to provide the short access times required to achieve the above data rates that exceed the capabilities of current silicon-based DRAMs. For proper operation clock skew must be eliminated, therefore, a 2-phase laser driven optical fiber distribution network has been considered. In addition, the photodetectors and amplifiers driving the CCDs must have speeds that do not compromise the access times of the CCD registers. To meet all requirements the design was implemented with optical fiber v-groove coupling to the MSM monolithic detectors and high-speed preamplifiers that are fabricated with the same technology as used for the fabrication of the CCDs.
A new class of accelerators Undulated Induction Accelerators (UNIAC -- EH-accelerators) is proposed as a basis for intense X-ray flash sources. Apart from X-ray sources these accelerators can be used for cooling (with simultaneous acceleration) of electron and ion beams, for forming high intensity relativistic beams of neutral molecules, neutrons and plasma fluxes, etc. The key idea of EH-accelerators is the utilization of undulated forms of trajectories of the accelerated particles. They may be trajectories of sinewave form, spiral form, and more complex spatial forms. It is clear that characteristic parameters of modern materials (permanent magnets, accelerator ferrites, and superconductors) allow construction of especially compact, and, at the same time, reliable, and relatively inexpensive acceleration systems in the energy range from hundreds keV to a few GeV. The possibility of constructing compact high intensity X-ray flash sources on the basis of EH-accelerators is substantiated for realization. Special schemes for forming pico- and nano-second intense X-ray pulses are proposed and analyzed. The project peculiarities and state of a preliminary experiment are discussed.
The semiconductors gallium arsenide and polycrystalline diamond can both be obtained in a high resistivity form suitable for the fabrication of photosensors and detector arrays for the ultraviolet region of the electromagnetic spectrum. These materials have different energy bandgaps and chemical properties which make them complementary partners in providing photodetectors for coverage of the spectral range from near 100 nm in the vacuum ultraviolet to the near infrared at 870 nm. The readily available forms of these two semiconductors are different. GaAs is available in the form of single crystal wafers with uniform properties while polycrystalline diamond in a tight packing of crystallites with varying orientations providing only an average uniformity on the micron scale determined by the size of the crystallites. The GaAs MSM detectors were studied for use in monolithic GaAs-based charge-coupled device scanners for the ultraviolet spectroscopy. The polycrystalline diamond MSM devices are being investigated for hybrid scanners on silicon for the vacuum ultraviolet.
Crystalline diamond has some unique and extreme properties that make it an attractive semiconductor in certain electronic applications such as in high-power systems and high-temperature environments. However, since a source of low-cost single crystal diamond does not exist, its widespread use is not commercially attractive. A cheaper form of diamond is polycrystalline diamond, which has been recently routinely grown on silicon by the high- pressure microwave-source plasma deposition technique. Large- grain thick polycrystalline films have been obtained with properties approaching those of single-crystal diamond. This report describes results obtained from optical and electrical methods used in evaluating these films for use as ultraviolet radiation sensors and as a capacitor dielectric.
Metal-Semiconductor-Metal (MSM) photodetectors on semi-insulating gallium arsenide (SIGaAs) have found widespread application as front-end detectors in receivers for optical fiber communications. Their major attributes are (a) simplicity of design and construction, (b) high responsivity, and (c) high speed of response. In this paper the performance of MSM detectors at short wavelengths is examined and considerations are given for their use in GaAs charge-coupled-device (CCD) imagers. The simplicity of their structure allows MSM detectors to be easily integrated with two-phase meander channel CCD registers in GaAs for production of high speed light scanners. Test results show that GaAs MSM detectors have high sensitivity in the wavelength range from 200 to 800 nm and good linearity over three orders of magnitude variation of the incident intensity. These features make MSM detectors potential candidates for both linear and 2-D light scanners for ultraviolet (UV) spectrophotometry and astronomy.
The design, fabrication, and operation of a two-phase meander-channel CCD imager on GaAs are described. The fabrication process is based on the use of anodic oxidation for producing thin dielectric isolations between close-packed Schottky-barrier metal electrodes and the employment of recessed gates for producing self-aligned potential barriers between the adjacent charge wells of the meander channel. Additionally, the semiinsulating property of GaAs is utilized in order to produce the high-speed photoconductive sensors. It is shown that such imagers can have unit cell sizes and pixel densities comparable to their silicon counterparts but offer the speed of performance higher by about one order of magnitude.