Engineering Commons^™

Pulsed Laser Annealing Of Gaas Implanted With Se And Si, Andrzej Rys, Yanan Shieh, Alvin Compann, Huade Yao, Ajit Bhat

Department of Electrical and Computer Engineering: Faculty Publications

Carrier activation and mobility were studied by Raman spectroscopy and the Hall effect in pulsed laser annealed samples of GaAs implanted with doses of Si and Se from 2.2. x 10¹² to 6.0 x 10¹⁴ cm^-2. The samples were annealed using a pulsed XeCl excimer laser ( = 308 nm) and a pulsed dye laser (=728 nm) with energy densities from 0.06 to 0.9 J/cm² and pulse durations of about 10 ns. Very high carrier concentrations of 3 x 10¹⁹ and 1.5 x 10¹⁹ cm^-3 were obtained for the best n-type GaAs …

Theoretical Model For The Images Formed By A Spherical Particle In A Coherent Imaging System: Comparison, Scott Alan Schaub, D. R. Alexander, J. P. Barton

Department of Electrical and Computer Engineering: Faculty Publications

A simple theoretical model is presented that allows calculation of the image produced by a spherical absorbing particle illuminated by monochromatic, coherent laser light. Results presented in this paper are restricted to a singe-lens imaging system, although generalization to more complex imaging system configurations would be straightfoward. The method uses classic Lorenz-Mie scattering theory to obtain the electromagnetic field external to an absorbing spherical particle and a Fourier optics approach to calculate the intensities in the image plane. Experimental results evaluating focus characteristics are examined for 50 um diameter water droplets using an N2 laser imaging system in conjunction with …

An Exact Analysis For Efficient Computation Of Random-Pattern Testability In Combinational Circuits, Sharad C. Seth, Bhargab B. Bhattacharya, Vishwani Agrawal

CSE Conference and Workshop Papers

Experimental evidence shows that low testability in a typical circuit is much more likely due to poor observability than poor controllability. Thus, from theoretical and practical standpoints, it is important to develop an accurate model for observability computation. One such model, in terms of supergates, is proposed in the first part of this paper thus complimenting our earlier work. It is now possible to obtain exact random-pattern testability for each line in a circuit.

The second part of the paper analyzes the supegate structure of a circuit from a graph theoretic viewpoint. Finding a supergate is related to determining the …

Study Of Mo, Au, And Ni Implanted Molybdenum Laser Mirrors By Spectroscopic Ellipsometry, Paul G. Snyder, George H. Bu-Abbud, Jae Oh, John A. Woollam, David Poker, D. E. Aspnes, David Ingram, Peter Pronko

Department of Electrical and Computer Engineering: Faculty Publications

The implantation of 150 kev molybdenum ions into polished molybdenum laser mirrors is found to increase the complex dielectric constant in the visible spectrum. Analysis using the Bruggeman effective medium approximation demonstrates that the increase is due to surface smoothing and that the surface is made nearly atomically smooth by a fluence of 5 x 10¹⁵ /cm². Implantation of Au at 1Mev caused considerable microscopic roughening, as well as a change in the bulk optical properties. 3 MeV Ni ion implantation caused only a slight surface roughening. A thin dielectric film (probably a hydrocarbon) is found to …

Atomic Hydrogen Storage, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Atomic hydrogen, for use as a fuel or as an explosive, is stored in the presence of a strong magnetic field in exfoliated layered compounds such as molybdenum disulfide or an elemental layer material such as graphite. The compound is maintained at liquid temperatures and the atomic hydrogen is collected on the surfaces of the layered compound which are exposed during delamination (exfoliation). The strong magnetic field and the low temperature combine to prevent the atoms of hydrogen from recombining to form molecules.

Electronic Properties Of Metal Chloride Intercalants Of Graphite*, **, John A. Woollam, M. B. Dowell, A. Yavrouian, A. G. Lozier, G. Matulka

Department of Electrical and Computer Engineering: Faculty Publications

The Shubnikov-deHaas (SdH) effect has been used to study the electronic properties of graphite intercalated with PdC1₂ (stage 3), FeC1₃ (stages 2, 4, 6, and 11), CuC1₂ (stage 1), and WC1₆ (stage 5). For the palladium chloride, ferric chloride, and copper chloride intercalants the SdH spectra are similar: these show frequencies of approximately, 27, 80, 380, and 550 Tesla for fields parallel to the c-axis. The effective masses have been measured for each of these carriers, and are of the order of 0.1 m₀, where m₀ is the free electron mass. These carriers …

Atomic Hydrogen Storage Method And Apparatus, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Atomic hydrogen, for use as a fuel or as an explosive, is stored in the presence of a strong magnetic field in exfoliated layered compounds such as molybdenum disulfide or an elemental layer material such as graphite. The compound is maintained at liquid helium temperatures and the atomic hydrogen is collected on the surfaces of the layered compound which are exposed during delamination (exfoliation). The strong magnetic field and the low temperature combine to prevent the atoms of hydrogen from recombining to form molecules.

Sio2-Si Film-Substrate Single-Reflection Retarders For Different Mercury Spectral Lines, A.R.M. Zaghloul, R.M.A Azzam

Department of Electrical and Computer Engineering: Faculty Publications

Design parameters for SiO₂- Si film-substrate single reflection retarders for several mercury spectral lines are presented. An example of an angle-of-incidence tunable retarder (AITR) capable of multiple wavelength operation (MWO) is reported Simple, approximate formulae for calculating film-substrate retarder design parameters (least film thickness d' and incidence angle) are presented.

Hall Effect Magnetometer, John A. Woollam, Harry A. Beale, Ian L. Spain

Department of Electrical and Computer Engineering: Faculty Publications

A magnetometer utilizing a single crystal of Bi²Se³ having a rhombohedral crystal structure is described along with a method for making such a device. The Bi²Se³ has a positive or negative Hall coefficient and a carrier concentration of about 10¹⁸to10²⁰ per cubic centimeter.