PPS-FAS is a local, short-term scheduling system inserted between the factory-level production planning and the real-time control system of a plant. In this paper the heuristic algorithm used by PPS-FAS to allocate the weekly production orders to the single days is described. The algorithm operates in two phases: the first phase generates an intermediate solution allocating jobs to the production days according to the objective of balanced utilization of all machines within each day; the second one improves the solution with respect to the objective of uniform utilization of all machines along the planning horizon.

Fermi-level pinning by misfit dislocations at GaAs interfaces has been investigated. ${n}^{+}$-GaInAs was used to control the misfit dislocation density by varying of composition and epilayer thickness. Interfaces with zero or low dislocation densities are Ohmic to current flow, and become rectifying with increasing dislocation density. The "Schottky barrier height" increases with dislocation density in accordance with a simple physical model which assumes Fermi-level pinning at the dislocation.

Numerical calculations have been made of the effect of grain size on the short-circuit current and the AM1 efficiency of polycrystalline thin-film GaAs and InP (2 µm thick) and silicon (25 µm thick) p-n junction solar cells. Junction solar cells are seen to be more efficient than Schottky-barrier cells, due to the higher dark current associated with Schottky diodes. GaAs shows the highest efficiency and both GaAs and InP attain 90 percent of their maximum efficiencies at a grain size of 10 µm, while silicon requires grain sizes of 200 µm to attain 90 percent of maximum efficiency. However, the deleterious effect of poor lifetimes and mobilities is less for silicon polycrystalline cells than for the direct-bandgap devices.

Device characteristics calculated from a one-dimensional dynamic simulation, incorporating space charge effects, of the gaseous discharge occurring at an isolated cell of an ac gas discharge panel are presented. The theoretical model shows all the qualitative features associated with plasma panels, and the quantitative agreement with experimental data inspires confidence in the general validity of the method.

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation J. M. Woodall, C. Lanza, J. L. Freeouf; Abstract: Electrical properties of the Ga–GaAs interface immersed in electrolytic solutions. J. Vac. Sci. Technol. 1 July 1978; 15 (4): 1436. https://doi.org/10.1116/1.569802 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAVS: Science & Technology of Materials Interfaces and ProcessingJournal of Vacuum Science and Technology Search Advanced Search |Citation Search

Bistability in gas-discharge cells is discussed from a general viewpoint. The physical mechanisms controlling the extent of this bistable range are examined by performing numerical simulations of the discharge dynamics in ac plasma panel cells under various assumed conditions. For the particular case of the commonly used neon + 0.1-percent argon mixture, the results give realistic bistable operating margins only when all three of the following conditions are satisfied: 1)incorporation of the electric-field distortion due to space charge; 2) inclusion of the dependence of the secondary-emission coefficient, γ, on the reduced electric field,E_{c}/p_{0}, at the cathode; and 3) assumption of an insignificant value of γ for argon ions in comparison to that for neon ions.

Numerical calculations have been made of the effect of grain size on the short-circuit current and the AM1 efficiency of polycrystalline thin film InP, GaAs, and Si Schottky barrier solar cells. Si cells 10 µm thick are at best 8 percent efficient for 100-µm grain sizes; 25-µm-thick Si cells can be about 10 percent efficient for this grain size. GaAs cells 2 µm thick can be 12 percent efficient for grain sizes of 3 µm or greater.

The details and results for a one-dimensional numerical analysis of the gaseous discharge occurring at a single intersection of an ac gas panel are reported. A particular object of the program is the determination of the electric field magnitude as a function of both position and time, taking into account the field distortion due to the space charge. The calculations are based on the Townsend avalanche mechanism but omit the dynamic role of metastable neon atoms in a Penning gas mixture. The calculated electrical properties of the panel are compared with experimental values.

Abstract : Experiments on the heat treatment effects in oxygen grown GaAs have shown that the compensating acceptor present in the material is due to a chemical impurity which occurs during growth but is probably not the result of contamination by the crystal growth vessel. Electron microscope examination of both as grown and heat treated GaAs show no detectable difference between the two. The observed dislocation density is about 10 to the 5th power lines cm to minus 2, or, on the average, one line per device. A technique of fabrication of Gunn effect devices using a solution regrowth technique for making contacts to the bulk GaAs has been tried but so far yields a high resistance layer at the interface. Epitaxial devices have been operated as both pulsed and CW oscillators and devices fabricated from heat treated material having a positive temperature coefficient of resistivity have been operated CW with a power output of 57 milliwatt at 2.5 GHz with 1% efficiency. (Author)

between two species of defects. Applica- tions of the theory are made to defects of various point symmetries in cubic crystals, and a number of specific ex- amples are discussed to illustrate each type of defect sym- metry. The usefulness of the theory is that it enables one to calculate the values of the components of the X-tensor from experimental information and the defect symmetry. Typical values of these h-parameters range from lo-* to