Hall Effect

The generation of the Hall field in a semiconductor slab in response to the charge carrier separation under the Lorenz force action. (Magnetic field normal on the figure plane)

The Hall Effect is a galvanomagnetic effect consisting in the generation of an electrical field / voltage (Hall field / voltage) across an electronic conductor placed in external, non-collinear magnetic and electric fields. From the simultaneously performed Hall effect and DC electrical resistance measurements, the charge carrier concentration and their mobility can be evaluated. Their dependence on the target gas concentration show how much each of them contribute to the gas response of the conductometric metal oxide (MOX) gas

sensors. According to our and literature data the main role in the MOX gas sensing is played by the charge carrier concentration.




Hall sample for operando measurements:

VH1-VH2 : 1st Hall voltage electrode pair

VH1-VH2 : 2nd Hall voltage electrode pair

V1-V2 : Applied voltage electrodes

I1-I2: Current injection electrodes

The CO response of a polycrystalline SnO2 thin film prepared by vacuum thermal deposition when operated at 200°C in synthetic air. The gas behaviour correspond to the n-type conductivity determined by Hall Effect. [2]
The ozone response of a granular In2O3 thick film, screen printed from a sol gel material with rhombohedric cristallyne structure when operated at 200°C in synthetic air. [3]

Related References

  • Characterization of granular metal oxide semiconductor gas sensitive layers by using Hall effect based approaches, A. Oprea, N. Barsan and U. Weimar, J. Phys. D: Appl. Phys., 40, 2007, 7217-7237.

  • Conduction model of SnO2 thin films based on conductance and Hall effect measurements, A. Oprea, E. Moretton, N. Barsan, W.J. Becker, J. Wöllenstein and U. Weimar, Journal of Applied Physics, 100, 2006, art. no. 033716.

  • Transport and gas sensing properties of In2O3 nanocrystalline thick films: A Hall effect based approach, A. Oprea, A. Gurlo, N. Barsan, U. Weimar, Sensors and Actuators B, 139, 2009, 322-328.