Frequency Multiplexed simultaneous Hall effect and resistivity transient measurements for van der Pauw samples
ORAL
Abstract
Simultaneous measurement of different contact configurations using frequency multiplexing enables continuous full transport characterization of samples under time-varying conditions.
Non-switching van der Pauw technique that was demonstrated in 1998 enabled simultaneous acquisition of both van der Pauw configurations and hence measuring of the sheet resistance and the level of anisotropy in an arbitrarily shaped sample. The method introduced here goes one step further and makes use of two different frequencies and three lock-in amplifiers to measure not only the sheet resistance, but also two conjugate transverse configurations. Due to Onsager – Casimir reciprocity relations, conjugate transverse information allows accurate calculation of Hall slope at any fixed magnetic field. Since mobility and the carrier concentration can be derived from these measurements each quantity can be analyzed separately and to distinguish carrier density transients from mobility transients. This method could also be utilized to examine transport transients due to any other time resolvable variables such as but not limited to gate biasing, temperature, and pressure variations.
Non-switching van der Pauw technique that was demonstrated in 1998 enabled simultaneous acquisition of both van der Pauw configurations and hence measuring of the sheet resistance and the level of anisotropy in an arbitrarily shaped sample. The method introduced here goes one step further and makes use of two different frequencies and three lock-in amplifiers to measure not only the sheet resistance, but also two conjugate transverse configurations. Due to Onsager – Casimir reciprocity relations, conjugate transverse information allows accurate calculation of Hall slope at any fixed magnetic field. Since mobility and the carrier concentration can be derived from these measurements each quantity can be analyzed separately and to distinguish carrier density transients from mobility transients. This method could also be utilized to examine transport transients due to any other time resolvable variables such as but not limited to gate biasing, temperature, and pressure variations.
*This work was supported in part by NSF DMREF-1729016. It also made use of the NUFAB facility of Northwestern University’s NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the IIN, and Northwestern’s MRSEC program (NSF DMR-1720139).
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Presenters
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Can C Aygen
- Northwestern University
- Northwestern University Department of Electrical and Computer Engineering