HIGH-PRECISION LATTICE-PARAMETER MEASUREMENTS ON GALLIUMARSENID BY NEUTRON BACKSCATTERING

A new four-counter-method was developed for lattice parameter measurements on GaAs-LEC-crystals reaching an accuracy of DELTA-a/a almost-equal-to 10(-7). A linear decrease of DELTA-a/a = 2 x 10(-6) was obtained with increasing stoichiometry in a region ranging from a composition X(As) = 0.49665 (Ga-rich) to X(As) = 0.50155 (As-rich). For the first time crystal instead of melt stoichiometry was investigated.