Hall and field-effect mobilities in few layered p-WSe 2 field-effect transistors

N. R. Pradhan, D. Rhodes, S. Memaran, J. M. Poumirol, D. Smirnov, S. Talapatra, S. Feng, N. Perea-Lopez, A. L. Elias, M. Terrones, P. M. Ajayan, L. Balicas

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Abstract

Here, we present a temperature (T) dependent comparison between field-effect and Hall mobilities in field-effect transistors based on few-layered WSe2 exfoliated onto SiO2. Without dielectric engineering and beyond a T-dependent threshold gate-voltage, we observe maximum hole mobilities approaching 350 cm2 /Vs at T = 300 K. The hole Hall mobility reaches a maximum value of 650 cm2 /Vs as T is lowered below ∼150 K, indicating that insofar WSe2 -based field-effect transistors (FETs) display the largest Hall mobilities among the transition metal dichalcogenides. The gate capacitance, as extracted from the Hall-effect, reveals the presence of spurious charges in the channel, while the two-terminal sheet resistivity displays two-dimensional variable-range hopping behavior, indicating carrier localization induced by disorder at the interface between WSe2 and SiO2. We argue that improvements in the fabrication protocols as, for example, the use of a substrate free of dangling bonds are likely to produce WSe2-based FETs displaying higher room temperature mobilities, i.e. approaching those of p-doped Si, which would make it a suitable candidate for high performance opto-electronics.

Original languageEnglish (US)
Article numbersrep08979
JournalScientific reports
Volume5
DOIs
StatePublished - Mar 11 2015

All Science Journal Classification (ASJC) codes

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    Pradhan, N. R., Rhodes, D., Memaran, S., Poumirol, J. M., Smirnov, D., Talapatra, S., Feng, S., Perea-Lopez, N., Elias, A. L., Terrones, M., Ajayan, P. M., & Balicas, L. (2015). Hall and field-effect mobilities in few layered p-WSe 2 field-effect transistors. Scientific reports, 5, [srep08979]. https://doi.org/10.1038/srep08979