Characterization of Electrical Properties of Suspended
ZnO Nanowires Using a Nanorobotic Manipulation System Inside a Scanning
Electron Microscope for Nanoelectronic Applications
posted on 2022-01-20, 12:34authored byAristide Djoulde, Tebogo Lucky Mamela, Weilin Su, Lingli Kong, Hongzhou Wang, Jinbo Chen, Jinjun Rao, Pengfei Zhao, Li Ma, Jun Yang, Zhiming Wang, Mei Liu
Electrical
characterization of semiconducting oxide nanowires (NWs)
is mostly performed using complex techniques, which necessitates a
series of costly nanofabrication procedures. In this work, with the
aim to provide a low-cost, feasible, facile, and reproducible approach
for enabling the study of NW electrical properties, we report direct
electrical measurements on individual and overlapped suspended zinc
oxide NWs (ZnO NWs). We have succeeded in constructing both two- and
three-terminal devices simply by employing tungsten (W) nanoprobes
with the aid of a nanomanipulation system embedded inside a scanning
electron microscope’s vacuum chamber. Stable contacts were
established using the Joule heating effect and e-beam exposure at
the junctions between the NW and the pre-cleaned W tips. P-channel
field-effect transistor devices were achieved with an on–off
current ratio of ∼101, a threshold voltage (>1.5
V), a transconductance of ∼16 μS, a sub-threshold swing
of ∼220 mV/decade, and field-effect carrier mobility roughly
estimated to be around 926.4 cm2/(V·s) after correction
for contact resistances/optimization. The average resistivity of ZnO
NWs was calculated to be ∼2.23 × 10–2 Ω·cm for NWs with diameters between 70 and 500 nm. Besides,
we have demonstrated a contact resistance of ∼19.60 kΩ
and a Schottky barrier height of ∼0.37 eV present at W/ZnO
NW interfaces. The contact resistance between two overlapped ZnO NWs
was estimated to be ∼283 kΩ, which is relatively higher
than that offered between W/ZnO NWs. This work provides a solid experimental
procedure to address true intrinsic electrical properties at metal/semiconductor
interfaces, and our findings have potential applications in next-generation
3D suspended ZnO NW-based nanoelectronic devices.