X-ray study of antiphase boundaries in the quadruple-period ordered GaAs0.87Sb0.13 alloy

The x-ray diffraction intensity from antiphase boundaries (APBs) in a quadr uple-period ordered GaAsSb alloy is derived introducing statistical probabi lities for these APBs and their associated phase shifts. Through experiment al fits, we obtain an average distance between the neighboring APBs of appr oximately 130, 400, and 5 nm along [110], [-110], and [001] directions, res pectively. The short distance along the [001] growth direction leads to a n arrow streak along [001] in an intensity contour map. In addition, we find that the APBs broaden the ordering peaks, while their effect on the intensi ty ratio between the ordering peaks is negligible. Static atomic displaceme nts, associated with bond length disparities are also included in the calcu lations. (C) 2001 American Institute of Physics.