UC Riverside

Indium Antimonide (InSb) nanowires with a diameter ranging from 30 nm to 200 nm, were synthesized by electrochemical disposition in anodized alumina and polycarbonate porous membranes. In addition, epitaxial single crystalline InSb nanowires with diameters ranging from 5 nm to 100 nm, were synthesized by chemical vapor deposition (CVD) using Au nanoparticles as catalyst. Structural and material characterization of InSb nanowires was carried out by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Electrical characterization of InSb nanowires was conducted by fabricating nanowire field effect transistors (FETs) by electron-beam lithography and direct metal deposition assisted by focused ion-beam (FIB). Conductive atomic force microscopy (CAFM) was employed in current-voltage (I-V) measurements of InSb nanowires as a local contact electrode measuring conductivity of a short cannel InSb nanowire. In addition, CAFM probe tip was also used as a local gate electrode to InSb nanowire FET. Temperature-dependent I-V measurements were conducted to elucidate the transport mechanism through the metal contact-nanowire junction. Rapid thermal annealing was applied for fabricating Ohmic contacts to InSb nanowires.

Depletion mode n-type back-gated FETs based on CVD grown InSb nanowires, exhibited high ION/I_OFF ratio of 10⁶, a subthreshold slope as low as 90 mV/dec, and electron mobility as high as 110 cm²V^-1s^-1. Diameter-dependent dependent I-V measurements were performed on the InSb nanowires, revealing the correlation between electron mobility, doping concentrations and nanowire diameter.

InSb nanowire-based FET chemical sensors were used for detection of water, Isopropanol, and Acetone vapors. The mechanism of operation of these sensor devices was investigated. In addition, Pt nanoparticle decorated InSb nanowire sensors were employed for detection of 0.1% H₂ gas. The performance of InSb nanowire sensor was compared to a graphene-based Hydrogen sensor.