Tuning the electrical properties of ZnO-Si nano-contacts and its effect on field electron emission from ZnO nanowires

摘要

ZnO nanowire (NW) is one of the promising cathode materials for vacuum microano electronic devices. Optimization on its field emission performance is one of the important issues. In present study we explored the effect of ZnO-Si (n⁺⁺ doped) nanojunctions electrical properties on field emission. Arrays of individual ZnO NWs on Si nanorods were fabricated. The electrical and field emission measurements were in-situ performed using nano-manipulated probes. The ZnO-Si n-n junction showed a lower junction barrier of 0.3∼0.6 eV, with good uniformity of 50% in electrical properties. Moreover, by applying strain on the Si nanorod to narrow its band gap, the effective contact resistance of the ZnO-Si nanojunction was dramatically decreased up to 10 times at a strain of 10%. The junction barrier was decreased to ∼0.1 eV, showing significant enhancement on field electron emission. This work directly demonstrated that (i) the effect of electrical nano-contact is of great important for vacuum nanoelectronic devices; (ii) heavily n-type doped semiconductor with narrower band is promising be used as cathode electrode.