We report on the transport properties of a single ZnO nanowire (NW) measured as a function of the length/square of the radius ratio via the transmission line method (TLM). The specific contact resistance of FIB-Pt contacts to the ZnO NWs is determined to be as low as 1.1 x 10(-5) Omega cm(2). The resistivity of the ZnO NWs is measured to be 2.2 x 10(-2) Omega cm. ZnO NW-based UV photodetectors contacted by FIB-Pt with a photoconductive gain as high as approximately 10(8) have been fabricated and characterized.

We demonstrated a nanocontacting scheme using a focus ion beam (FIB) system without further heat treatment for ZnO nanowires. This scheme includes Ga ion surface modification and direct-write Pt deposition induced by Ga ion, leading to an Ohmic nanocontact with a specific contact resistance as low as 2.5 × 10(-6)Ω cm(2). Temperature-dependent measurements show that the transport of the FIB-Pt contact on the ZnO nanowire with local surface modification is governed by field emission tunneling. Taking advantage of area-selected and room-temperature processes, Ga ion surface modification and direct-write Pt deposition using a FIB system demonstrates a feasible Ohmic scheme.

In this study, four additives—montmorillonite, activated carbon, and the layered double hydroxides (LDHs), Mg2Fe–LDH and Mg2Al–LDH—were tested for their ability to promote surfactin production in a Bacillus subtilis ATCC 21332 culture. Among these tested materials, the addition of 4 g/L of the Mg-Fe LDH, which featured an Mg/Fe molar ratio of 2:1, produced the highest surfactin yield of 5280 mg/L. During the time course of B. subtilis cultivation with the added LDH, two phases of cell growth were evident: Growth and decay. In the growth phase, the cells grew slowly and secreted a high amount of surfactin; in the decay phase, the cells degraded rapidly. The production in the presence of the Mg2Fe–LDH had three characteristics: (i) High surfactin production at low biomass, indicating a high specific surfactin yield of 3.19 g/g DCW; (ii) rapid surfactin production within 24 h, inferring remarkably high productivity (4660 mg/L/d); and (iii) a lower carbon source flux to biomass, suggesting an efficient carbon flux to surfactin, giving a high carbon yield of 52.8%. The addition of Mg2Fe–LDH is an effective means of enhancing surfactin production, with many potential applications and future industrial scale-up.

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