Studies of Dendrites Grown Utilizing Intersecting Twin Planes

Abstract

Dendrites of Ge, Si, and the III–V intermetallic compounds have been grown in the form of platelets and ribbons utilizing the twin plane re-entrant edge mechanism [1–3]. In addition, certain metals, such as the fcc metals [4], Cd [5], and Bi [6], have been grown by this technique. The platelets and ribbons are lathlike with two or more twin planes lying parallel to the main faces [2]. Other elongated shapes of these materials have been grown and found to contain intersecting twin planes. Faust and John [7] and later Faust et al. [8] gave many possible configurations of intersecting twin planes. The number of intersecting twin planes can be from two to five for the diamondlike and fcc lattices. One could have more than five twins, but this means more grain boundaries in addition to the twin boundaries and are of no interest to this study. Unlike the dendrites with parallel twin planes which grow in the (211) directions, and dendrites with no twin planes that grow in the (100) directions, those with the intersecting twin planes grow in the (110) directions. The angles between the intersecting twins will be either 70°32′ or 109°28′. The sum of the angles for a crystal with five intersecting twin planes is only 352°40′, lacking 7°20′ to complete the required 360°.