Lattice-mismatched GaInAs and A InAs layers will be grown on InP and GaAs substrates by MBE and MOCVD. Different-density misfit dislocations will be intentionally introduced. Samples will be nondestructively characterized by the x-ray rocking curve technique and the rocking curve topography technique, and cleaned and cleaved. Thin metal film Ohmic or Schottky contacts will be formed and I-V or C-V characteristics will be studied. Expected results are (l) Schottky barrier heights for the ternary epilayer-substrate junction as a function of the misfit dislocation density, (2) effects of the misfit dislocations in the electrical characteristics for p-i-n and n-n+-n heterostructures, (3) the critical thickness of the ternary epilayer as a function of the misfit, and (4) assessment of the nondestructive x-ray technique in measurements of the misfit dislocations. This proposed project is expected to improve the present understanding of the effects of the misfit dislocations in device performance and provide further and accurate data on the Schottky barrier heights for metal-ternary and ternary-substrate contacts.