Molecular beam epitaxial growth and characterization of indium antimonide on gallium arsenide

Abstract

Described in this thesis are the molecular beam epitaxial growth and characterization of InSb on GaAs substrates. The growth conditions and mechanisms of this highly lattice-mismatched system are detailed. Structural, electrical, and optical properties of the InSb epilayers are characterized by transmission electron microscopy (TEM), X-ray rocking curves, Hall measurements, photoluminescence (PL), and transmission measurements. The TEM study reveals pure edge-type, instead of the common 60$\sp\circ$-type, misfit dislocations at the InSb/GaAs interfaces. The reason for the formation of these misfit dislocations are given. Electrical measurements show that dislocation scattering is an important scattering mechanism in the epilayers. A charged dislocation scattering is proposed to explain the temperature and carrier concentration dependence of electron mobility. Low temperature PL shows a single band-edge transition similar to that of bulk InSb, indicating very little or no residual strain in the epilayers.

Indium antimonide p$\sp{+}$-n diodes have been successfully fabricated on as-grown and ion-implanted wafers. The electrical characteristics of these diodes compare favorably to those reported on similar devices. Further improvement can be achieved by proper surface passivation. Indium antimonide-Gallium arsenide p-n, p-p, and n-n heterojunctions have also been prepared for this study with all of the junctions exhibiting excellent rectifying characteristics. From capacitance-voltage measurements, the band offsets of InSb/GaAs junctions have been, for the first time, determined experimentally.