Molecular-beam epitaxial growth of high-quality InSb on InP and GaAs substrates

Epitaxial layers of InSb have been grown in InP and GaAs substrates by molecular-beam epitaxy. The dependence of the epilayer quality on flux ratio, J_Sb4/J_In , was studied. Deviation from an optimum value of J_Sb4/J_In (∼2) during growth led to deterioration in the surface morphology and the electrical and crystalline qualities of the films. Room-temperature electron mobilities as high as 70 000 and 53 000 cm²/V s were measured in InSb layers grown on InP and GaAs substrates, respectively. Unlike the previous results, the conductivity in these films is n type even at T=13 K, and no degradation of the electron mobility due to the high density of dislocations was observed. The measured electron mobilities (and carrier concentrations) at 77 K in InSb layers grown on InP and GaAs substrates are 110 000 cm²/V s (3×10¹⁵ cm^-3) and 55 000 cm²/V s (4.95×10¹⁵ cm^-3), respectively, suggesting their application to electronic devices at cryogenic temperatures.