Quantitative measurements of nanoscale permittivity and conductivity using tuning-fork-based microwave impedance microscopy

Abstract

We report quantitative measurements of nanoscale permittivity and conductivity using tuning-fork (TF) based microwave impedance microscopy (MIM). The system is operated under the driving amplitude modulation mode, which ensures satisfactory feedback stability on samples with rough surfaces. The demodulated MIM signals on a series of bulk dielectrics are in good agreement with results simulated by finite-element analysis. Using the TF-MIM, we have visualized the evolution of nanoscale conductance on back-gated MoS field effect transistors, and the results are consistent with the transport data. Our work suggests that quantitative analysis of mesoscopic electrical properties can be achieved by near-field microwave imaging with small distance modulation.

Lithium-ion electrolytic substrates for sub-1V high-performance transition metal dichalcogenide transistors and amplifiers

“…The transistor-based measurements discussed above provide information on the global transport behavior over the entire channel area. In order to gain more insight on the gate-dependent local conductance, we have performed tuning-fork (TF) based microwave impedance microscopy (MIM) 50 , as schematically illustrated in Fig. 5a.…”

Visualization of Local Conductance in MoS2/WSe2 Heterostructure Transistors

“…In particular, an electrochemically etched tungsten tip was attached to a quartz tuning fork (resonant frequency ~ 32 kHz). A Zurich HF2L1 lock-in amplifier was used to control the tuning-fork tip to vibrate at its resonant frequency in the driving amplitude modulation (DAM) mode 45 . The topography feedback system was provided by a commercial AFM system (Park XE-70).…”

Electrically-functionalised nanoindenter dedicated to local capacitive measurements: Experimental set-up and data-processing procedure for quantitative analysis

“…One can notice that the stray capacitance is automatically withdrawn by working on this differential magnitude. This analytical method eliminates the stray capacitance without any fitting parameter or extensive setup calibration (to be compared to the works reported for instance in [20][21][22]), and should be suitable for the analysis of capacitance-measures acquired on any system subjected to a stray capacitance that is voltage-independent.…”

“…A pioneering attempt [17] to perform permittivity and alternating conductivity measurements on dielectric materials was spatially-limited by the large scale probe (circa 100 µm). Nanoscale Impedance Microscopy (NIM) has then been developed to characterize frequency-dependent charge transport and polarization mechanisms in dielectric films [3,4,10,[18][19][20]. Contrary to SCM, the NIM technique provides the measurement of both resistance and capacitance of the tip-to-sample interface: both the amplitude and phase of the current induced by an alternating bias are measured.…”

“…The same team proposed a dual-scan procedure to remove environmental effects [24]. Extensive calibration processes based on analytical or numerical modelling have also been developed to obtain quantitative capacitive measurements [20][21][22].…”