Synthesis, Characterization and Applications of InSb Semiconductor Nanowires

Synthesis of InSb nanowires using a chemical vapor deposition technique, as a function of growth temperature and time, was investigated. High aspect ratio InSb nanowires, having a diameter of about 5-10nm, were grown at 400oC for 1 hr on InSb (111) substrate onto which 60nm Au particle was used as a metal catalyst. The synthesized InSb nanowires had zinc blend single crystal structure without any stacking faults, and they were covered with a thin (~1nm thick) amorphous layer. Electrical characterization of InSb nanowires was conducted utilizing a back-gated SNWFET. Device characterization demonstrated that NWs were n-type and exhibited a high ION/IOFF ratio of 106 and device resistance of 250 kΩ. Furthermore, room temperature detection of NO2 down to one part-per-million (ppm) using single crystalline n-type InSb nanowires (NWs) chemiresistive gas sensor fabricated by the combination of chemical vapor deposition and dielectrophoresis alignment techniques is investigated. The sensor devices showed an increase in resistance upon exposures to successive increment of NO2 concentration up to 10 ppm. The reduction in conductance of n-type InSb NWs exposed in NO2 atmosphere is made possible due to the charge transfer from the InSb NW surface to the adsorbed electron acceptor NO2 molecules. The demonstrated results suggest InSb NW as a promising candidate in sensing applications being environmentally friendly over existing arsenic and/or phosphorous-based III-V NW sensors