Showing papers on "Mass action law published in 1990"

Point-defect equilibrium during diffusion of purely substitutional impurities into elemental crystals.

Abstract: Diffusion of exclusively substitutional solutes (B) into elemental metallic or semiconducting matrices via exchanges with vacancies (V) is treated by starting from a quasichemical reaction which includes impurity-vacancy pairs (BV) as a third species, i.e., BV\ensuremath{\rightleftarrows}B+V. This approach enables us to answer the question whether during foreign-atom penetration the vacancy concentration of the host crystal remains in thermal equilibrium. Within the present concepts a distinction can be made between the BV-controlled and the V-controlled mode of the vacancy mechanism. It is shown that commonly the former case, in which vacancy equilibrium persists, is realized. In the V-controlled case the B incorporation is limited by the removal of excess isolated vacancies originating from dissociation of BV pairs. Conditions for the appearance of this diffusion mode are pointed out. We also discuss the role of dislocations as vacancy sinks, the validity of the mass-action law associated with the above reaction, and a possible influence of self-interstitials.

Intrinsic carrier concentration in Hg1−xCdxTe

Abstract: The effective mass of heavy holes has been determined on the basis of simultaneous analysis of the Hall coefficient and conductivity data obtained in the temperature region 100–300 K on well characterized p-type Hg1−xCdxTe (x≈0·2) samples. Its value is ≈0·7m0. The calculation of intrinsic carrier concentration for 0·19≦ x≦0·3 and 50 Kg ≦T≦ 300 K has been carried out using the above value of the effective mass of holes, Hansen's expression for the band gap and momentum matrix element from magneto-optical measurements.