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A structural investigation of compositionally graded InAs/sub x/Sb/sub 1-x/ buffer layers

Conference ·
OSTI ID:6662458

The preparation of high quality InAs/sub x/Sb/sub 1-x//InSb strained-layer superlattices (SLS's) which absorb in the 8--12 ..mu..m range was achieved through the use of compositionally graded buffer layers grown by MOCVD. Comparisons of surface morphology and the residual strain determined by double crystal x-ray diffraction were made between four types of graded buffer layers. Both the buffer layer thickness and composition profile were found to affect the formation of microcracks and dislocations. The relaxation in these buffers is less than expected from equilibrium models, but it is more complete in the continuously graded than in the step-graded layers. Residual strain in the InAs/sub x/Sb/sub 1-x//InSb SLS's was minimized by preparing InAs/sub y/Sb/sub 1-y/ buffer layers in which the parallel lattice constant of the strained buffer layer was closely matched to the parallel lattice constant of the SLS. 21 refs., 3 figs., 1 tab.

Research Organization:
Sandia National Labs., Albuquerque, NM (USA)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
6662458
Report Number(s):
SAND-88-1242C; CONF-881061-8; ON: DE89002890
Country of Publication:
United States
Language:
English