In this work, the excellent turn-on field (E on) of InSb nanowires can be attributed as follows: The high carrier concentration of the InSb nanowires with the Fermi level is located above the conduction band minimum, significantly reducing the effective electron tunneling barrier. Figure 5c

illustrates the band diagram of degenerate InSb nanowires. The large density of states in the InSb conduction EPZ-6438 clinical trial band (i.e., surface accumulation layer) causes a downward band bending near the surface region that eventually leads to lower the electron tunneling barriers. Additionally, the Fermi level is located above the conduction band minimum that can also improve the efficiency of tunneling at a low electric field. Next, the vertically aligned nanowires also play an important role. The high aspect ratio of the nanowires at applied electric field easily makes the electrons to accumulate on the surface and enhance significant field emission property. However, the density of nanowires must be moderate [46, 47]. Previous works reported that the electrostatic screening selleck kinase inhibitor effect increased the turn-on

field and decreased the overall emission current density of densely packed grown nanowires [48, 49]. This is because the applied electric field will overlap with that of the others. click here Consequently, the effective electric field of densely packed nanowires will be lowered compared to the stand-alone nanowires. Here, there is a reduced screening effect in the vertically aligned InSb nanowires due to a sufficient spacing between the emitters; meanwhile, there is the nanodimension structure with high aspect ratio. Therefore, the electron accumulation that occurs in the conduction band and sufficient spacing in aligned nanostructures can simultaneously enhance field emission property. Conclusions Single-crystalline InSb nanowires can be successfully

synthesized via the electrochemical method at room temperature. The I-V curve of the InSb nanowires based on the M-S-M model shows low GPX6 resistivity ρ of 0.07 Ω cm owing to the existence of Sb vacancies. Meanwhile, InSb nanowires have a high electron concentration of 2.0 × 1017 cm−3 and a high electron mobility of 446.42 cm2 V−1 s−1. Also, the energy bandgap increases from 0.17 to 0.208 eV due to the filling up of low-energy states in the conduction band by excess electrons. Thus, the enlargement of energy bandgap and high electron concentration reveal that the InSb nanowires are degenerate semiconductors with the Fermi level located above the conduction band minimum. The accumulation layer occurs at the surface of InSb nanowires. The surface accumulation layer in the InSb conduction band causes a downward band bending near the surface region that eventually leads to lowering of the electron tunneling barriers.