The intrinsic electrical properties of individual single-crystalline tin dioxide nanobelts, synthesized via catalyst-free physical vapor deposition, were studied and correlated to the surface oxygen deficiency with the presence of various ambient gases, especially hydrogen. Four-terminal field-effect transistor (FET) devices based on individual SnO 2 nanobelts were fabricated with SiO 2/Si as back gate and RuO 2/Au as contacts. Four-probe I-V measurements verify channel-limited transistor characteristics and ensure that the hydrogen gas sensing reflect electrical modification of the nanobelt channel. The demonstrated results of the intrinsic SnO 2 nanobelt based hydrogen sensor operating at room temperature provide useful information on the synthesis of room temperature chemo-resistive gas sensors with good sensitivity and stability. To evaluate the impact of surface gas composition on the electrical properties of SnO 2 nanobelts, their temperature-dependent resistivity (ρ), effective carrier mobility (μ eff) and effective carrier concentration (n e) were determined under different oxygen concentrations.
Bibliographical noteFunding Information:
The authors thank Dr. Olaf Wunnicke for valuable discussions of the finite element method of simulating the electrical field of the device and Drs. Stephan von Molnár and Cong Ren for assistance with the electrical measurements. This work was supported by NSF NIRT Grant No. ECS-0210332 and an FSU Research Foundation PEG grant .
- Electrical properties
- Surface properties