Eqilibrium Analysis of the TMGa-TMA1-AsH3-H2 Mocvd Epitaxial Growth System

1988 ◽  
Vol 131 ◽  
Author(s):  
Hyuk J. Moon ◽  
Thomas G. Stoebe ◽  
Brian K. Chadwick
Keyword(s):  
Gas Phase ◽  
Solid Phase ◽  
Total System ◽  
Method Of Calculation ◽  
System Pressure ◽  
Partial Pressures ◽  
Growth System ◽  
Effects Of Temperature ◽  
Temperature And Pressure ◽  
Thermodynamic Equilibrium State

ABSTRACTThe thermodynamic equilibrium state of the Ga-Al-As-C-H system was determined theoretically by means of an iterative equilibrium constant method. This method of calculation is presented and discussed. With very little operator input, the program is capable of computing the partial pressures of the gas-phase species present in the equilibrated system.In these calculations the system was considered to be saturated with solid-phase A1GaAs and included 58 plausible gas-phase intermediates which evolved from the initially present gas species; trimethylgallium, trimethylaluminum, arsine, and hydrogen. Temperature and total system pressure ranges investigated were 750–1100 K and 0.1 atm-1.0 atm, respectively. The effects of temperature and pressure variations, in addition to effects caused by changes in the appropriate atom ratios, have been delineated. The properties of this equilibrated system are compared with those from recent thermodynamic research efforts on AlGaAs systems consisting of only gaseous constituents.

On the theory of non-radiative transfer of electronic excitation

1973 ◽  
Vol 335 (1600) ◽  
pp. 51-66 ◽  
Keyword(s):  
Energy Transfer ◽  
Gas Phase ◽  
Cross Sections ◽  
Inelastic Collision ◽  
Energy Gap ◽  
Solid Phase ◽  
Exchange Interactions ◽  
Effects Of Temperature ◽  
Collisional Energy Transfer ◽  
Transfer Probability

In a previous paper, the Dexter-Förster theory was reformulated so that it can be used to discuss explicitly effects of temperature, isotope substitution and the energy gap between the excited donor and the ground state acceptor on the rate of energy transfer. In this paper, the equivalence of the two formulations is shown and some new results obtained from the reformulation are presented. The inelastic collision cross-sections for singlet-singlet, triplet-singlet, and triplet-triplet transfers have been obtained by using the first Born approximation. The relation between the quenching constant and the quenching cross-section is discussed. It is shown that for singlet-singlet and triplet-singlet transfers in the gas phase, both Coulomb and exchange interactions are important. The energy transfer probability in the solid phase and the quenching constants in the collisional energy transfer are compared. Some experimental results of the energy transfer measurements in the gas phase are discussed.

scholarly journals UV Enhancement of Surface Catalytic Polymerization of Ethylene

1988 ◽  
Vol 129 ◽  
Author(s):  
Parul Vora Purohit ◽  
Mordechai Rothschild ◽  
Daniel J. Ehrlich
Keyword(s):  
Thin Film ◽  
Fourier Transform ◽  
Gas Phase ◽  
Solid Phase ◽  
Catalytic Polymerization ◽  
Saturation Thickness ◽  
Partial Pressures ◽  
Rate Of Polymerization ◽  
Phase Chemical

ABSTRACTThe polymerization of ethylene on surfaces sequentially dosed with TiC14 and trimethylaluminum was studied by Fourier transform infrared spectroscopy. The polymer film was observed in situ as a function of time and under the influence of 254-nm cw radiation. The rate of polymerization and the saturation thickness of the polyethylene are strongly dependent on the order of dosing and the partial pressures of the reactants that form the catalyst. UV enhancement of polymerization was demonstrated to occur through two separate photochemical channels: gas-phase photolysis of the reactants and solid-phase chemical transformation of a noncatalytic thin film.

Palladium-catalyzed carbonylation of 1,5-cyclooctadiene. Effects of temperature and pressure

1991 ◽  
Vol 56 (3) ◽  
pp. 663-672 ◽  
Author(s):  
Curtis B. Anderson ◽  
Rade Marković
Keyword(s):  
Carbon Monoxide ◽  
Oxidative Carbonylation ◽  
Influence Of Temperature ◽  
Carbonylation Reaction ◽  
Palladium Catalyzed ◽  
Effects Of Temperature ◽  
Temperature And Pressure

The influence of temperature and carbon monoxide pressure on the course of oxidative carbonylation reaction of 1,5-cyclooctadiene in the presence of the palladium(II) salts as a catalyst, was investigated.

A polycentric growth model of gallium arsenide epitaxial layers from the gas phase with simultaneous diffusion, adsorption and chemical reaction

1988 ◽  
Vol 53 (12) ◽  
pp. 2995-3013
Author(s):  
Emerich Erdös ◽  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma
Keyword(s):  
Growth Rate ◽  
Gallium Arsenide ◽  
Epitaxial Growth ◽  
Gas Phase ◽  
Surface Reaction ◽  
Quantitative Description ◽  
The Other ◽  
Rate Equations ◽  
Impact Interaction ◽  
Partial Pressures

For a quantitative description of the epitaxial growth rate of gallium arsenide, two models are proposed including two rate controlling steps, namely the diffusion of components in the gas phase and the surface reaction. In the models considered, the surface reaction involves a reaction triple - or quadruple centre. In both models three mechanisms are considered which differ one from the other by different adsorption - and impact interaction of reacting particles. In every of the six cases, the pertinent rate equations were derived, and the models have been confronted with the experimentally found dependences of the growth rate on partial pressures of components in the feed. The results are discussed with regard to the plausibility of individual mechanisms and of both models, and also with respect to their applicability and the direction of further investigations.

DECOMPOSITION PRESSURES OF FERRIC SULPHATE AND ALUMINUM SULPHATE

1960 ◽  
Vol 38 (11) ◽  
pp. 2196-2202 ◽  
Author(s):  
N. A. Warner ◽  
T. R. Ingraham
Keyword(s):  
Gas Phase ◽  
Static System ◽  
Ferric Sulphate ◽  
Kcal Mole ◽  
Aluminum Sulphate ◽  
Temperature And Pressure ◽  
Pressure Changes ◽  
Mercury Manometer ◽  
Decomposition Pressure ◽  
Gas Pressures

The gas pressures over samples of anhydrous ferric sulphate and anhydrous aluminum sulphate have been measured in a static system, using a mercury manometer in which the exposed surface was covered with a flexible Pyrex bellows. The calculated ΔH for the decomposition of Fe2(SO4)3 was +135.4 kcal/mole. It was not possible to calculate the ΔH for the Al2(SO4)3 decomposition, because a discrete aluminum oxide with singular thermodynamic properties was not obtained.In the Fe2(SO4)3 system, the fraction of SO3 in the gas phase was found to be almost constant over the range of temperature and pressure changes used in the study.At any given temperature, the decomposition pressure over a ferric sulphate sample is greater than that over an aluminum sulphate sample, thus indicating that preferential decomposition of ferric sulphate should be thermodynamically feasible in mixtures of ferric sulphate and aluminum sulphate.

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