Effect of Poisons on Crystal Growth

Abstract

The effect of impurities is inexplicable by the accepted theory of crystal growth. In this report a mechanism is presented which describes the specific action of crystal‐growth poisons. By this model the step motion in growth is hindered and nucleation rate on an ideal surface is increased. To rationalize the effect of growth poisons it is necessary to postulate that complete monostep adsorption occurs at growth steps. In addition, the poison ion or molecule must present energetic and/or steric barriers to the addition of solute atoms so as to form an unpoisoned step by burying the adsorbed line of molecules.