ANOMALOUS HALL-EFFECT IN INSB LAYERS GROWN BY METALORGANIC CHEMICAL-VAPOR DEPOSITION ON GAAS SUBSTRATES

InSb epitaxial layers have been grown on GaAs substrates by low-pressu re metalorganic chemical vapor deposition. A 3.15-mum-thick film yield ed an x-ray full width at half maximum of 171 arcsec. A Hall mobility of 76 200 cm2/V s at 240 K and a full width at half maximum of 174 arc sec have been measured for a 4.85-mum-thick epilayer. Measured Hall da ta have shown anomalous behavior. A decrease in Hall mobility with dec reasing temperature has been observed and room-temperature Hall mobili ty has increased with thickness. In order to explain the anomalous Hal l data, and the thickness dependence of the measured parameters, the H all coefficient and Hall mobility have been simulated using a three-la yer model including a surface layer, a bulklike layer, and an interfac e layer with a high density of defects. Theoretical analysis has shown that anomalous behavior can be attributed to donorlike defects caused by the large lattice mismatch and to a surface layer which dominates the transport in the material at low temperatures.