We report the epitaxial growth of singlehyphen;crystal stoichiometric ZnGeAs2. The (001) ZnGeAs2layers were deposited by organometallic vaporhyphen;phase epitaxy on (100) GaAs. The epitaxy has specular surface morphology. The stoichiometric chemical composition has been confirmed by xhyphen;ray diffraction, electron microprobe, and Auger electron spectroscopy. Selectedhyphen;area electron diffraction patterns clearly indicate the chalcopyrite structure and that the lsqb;001rsqb; lattice direction is the growth direction. Xhyphen;ray diffraction indicates that thechyphen;direction lattice constant is 11.192 Aring; for our epitaxial material, which is an elongation of 0.35percnt; from the bulk material value of 11.153 Aring;. When stiffness constants for ZnGeAs2are approximated by those of GaAs, thischyphen;axis elongation can be explained by a contraction in theadirection induced by the 3.4times;10minus;3lattice mismatch between the ZnGeAs2epitaxy and the GaAs substrate. Absorptance and transmittance measurements indicate that this material has a direct band gap of approximately 1.15 eV and agrees well with previously reported values. Hall measurements show that the material isptype with roomhyphen;temperature hole mobilities up to 56 cm2thinsp;Vminus;1thinsp;sminus;1for a corresponding carrier concentration of 9times;1018cmminus;3. This mobility is slightly higher than previously reported for bulk material and attests to the high quality of this material.
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