It is not unlikely that certain refractory materials will display an optimum temperature of operation, representing a critical value for competing mechanisms that act to elevate and suppress the effective work function with temperature.It has been pointed out that for a highly ionized chemical species the chemical equilibrium of the plasma is only slightly affected by the absorption of free electrons by the dust particles.! With a partially ionized chemical species however, the absorption of plasma electrons by dust particles will increase the total electron concentration. Then Eq. (31) for electron absorption efficiency must be treated simultaneously with an equation describing the condition for chemical equilibrium. A rigorous treatment of the problem, for slight or moderate ionization of an active species, must take account of the temperature dependence of 1/18 and ni.
APPENDIXIf the Poisson equation (1) is supplemented with a uniform charge density in the space between dustand subject to the boundary conditions (3), we obtain the solution for r ~ a (A2)and to first order in a/ R, we finda result identical to Eq. (9), the latter expression for rp(a) obtained in the body of the paper with p given by the form (2) and KR«1. This suggests that for a«R and KR«1 the quantity rp(a) is rather insensitive to the detailed form postulated for the charge density p.Electron injection into p-type silicon at 76°K has been observed to reduce the lifetime degradation rate due to 60CO gamma irradiation at 76°K. By comparing isochronal annealing data between 76° and 300 0 K with similar data obtained by Watkins in EPR studies, the lifetime degradation at 76°K is seen to be due primarily to recombination through vacancies. Since the activation energy of motion of silicon vacancies is known to depend strongly on charge state, the injection-stimulated reduction in degradation rate at 76°K has been related to-vacancy reordering which occurs when the injected electron density is sufficiently large to modify the vacancy charge state from neutral (mobile above 160 0 K) to negative (mobile above 60 0 K). Quantitative estimates of the vacancy-reordering rate in the presence of excess electrons show this model to be consistent with the observed phenomena.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.