GROWTH AND CHARACTERIZATION OF In,,.&,-,Sb DEVICE STRUCTURES USING METALORGANIC VAPOR PHASE EPITAXY

m.2GaO8Sb epitaxial layers and thennophotovoltaic (TPV) device structures have been grown on GaSb and OaAs substrates by metalorganic vapor phase epitaxy (MOVPE). Control of the n-type doping up to 1 x 10 cm was achieved using diethyltellurium (DETe) as the dopant some. A Hall mobility of greater than 8000 cm /Vs at 77K was obtained for a 3 x 1017~m*3 doped In().2(&io,gSb layer grown on high-resistivity OaSb substrate. The Iq).2Ga0.8Sb epilayers directly grown on GaSb substrates were tilted with respect to the substrates, with the m u n t of t2t increashg with the layer thickness. Transmission electron microscopy (TEM) studies of the layen showed the presence of dislocation networks across the epiIayers parallel to the interface at different distances from the htaface, but the layers above this dislocation network were virtually frec of dislwadons. A strong carrelation between epi1;byer tilt and TPV device properties was found, with layers having mofe tilt providing better devices. The results suggest that the dislocations mving pardld to the interface cause lattice tilt, and control of this lam tilt may enable the fabrication of better quality device structures. 18 -3 2