Structural features of ∑ = 19, [110] GaAs tilt grain boundaries

∑ = 19, [110] tilt grain boundaries have been observed to facet parallel to particular planes; the facets lie along (3̄31̄)A/(33̄1̄)B, (5̄58)A/77̄4)B and (2̄27̄)A/(44̄5)B. The structural unit of the ∑ = 19 (3̄31̄)A/(33̄1̄)B [110] boundaries consists of 5- and 7-member rings, which are similar to the core structure of a/2[110] edge dislocations. The polarities in each grain on either side of the boundaries has been confirmed by CBED methods; a lower number of anti-site type cross-boundary bonds occur along the boundaries compared to when the polarity of one grain is reversed. The presence of 7-member rings and anti-site cross-boundary bonds results in a more open atomic structure at the boundary, shortening the distance between the first and the second {331} atomic planes from the boundary plane by 40%. © 2001 Kluwer Academic Publishers.