Local impedance imaging and spectroscopy of polycrystalline ZnO using contact atomic force microscopy

Abstract

A current detection scanning probe technique is developed that quantifies frequency-dependent local transport properties. The approach, referred to as nanoimpedance microscopy/spectroscopy (NIM), is based on impedance spectroscopy with a conductive atomic force microscopy (AFM) tip. NIM is applied to study the quality of a tip/surface contact and transport behavior of individual grains and grain boundaries in polycrystalline ZnO. Impedance spectra were measured in the frequency range 40 Hz to 110 MHz, and the grain boundary properties are studied by nonlinear fitting of experimental data to an equivalent circuit. Two-terminal measurements are performed in the vicinity of a single ZnO grain boundary and the Cole–Cole plot indicates two major relaxation processes attributed to grain boundary relaxation and tip/surface contact.

Nanoscale dielectric microscopy of non-planar samples by lift-mode electrostatic force microscopy

“…Among them, we can cite nanoscale capacitance microscopy [1][2][3], electrostatic force microscopy (EFM) [4][5][6][7][8][9][10], nanoscale impedance microscopy [11,12], scanning polarization force microscopy [13][14][15][16], scanning microwave microscopy (SMM) [17,18] and nanoscale non-linear dielectric microscopy [19]. These techniques have allowed measuring the electric permittivity with nanoscale spatial resolution on planar samples, such as thin oxides, polymer films and supported biomembranes [2][3][4]8,10], and on non-planar ones, such as, single carbon nanotubes, nanowires, nanoparticles, viruses and bacterial cells [20][21][22][23][24][25][26][27][28][29][30].…”

Local probing of ionic diffusion by electrochemical strain microscopy: Spatial resolution and signal formation mechanisms

“…A number of authors 18,19,20 have demonstrated the use of an AFM as a probe for local electrochemical impedance spectroscopy.…”

Comparison of Electrical Properties of Viruses Studied by AC Capacitance Scanning Probe Microscopy

“…Before and after carrying out capacitance measurements, the system conductance was checked by measuring impedances of bare Au plates. 13 We first analyzed the dielectric properties of polymer nanoparticles as a function of AC frequency to study a circuit model of our system (Figure 3). Capacitances of polystyrene (PS) and polymethylmethacrylate (PMMA) particles in the diameter of 100 nm were also compared at 90 % of humidity as controls, and the capacitance of PMMA appeared higher than the PS capacitance as shown in Figure 4-(a), which is consistent with the order of their dielectric constants, 2.6 and 3.12, respectively.…”

“…Illustration of the probe configuration and its circuit model of the AC capacitance SPM. C virus is capacitance of virus, CPE is a constant-phase element, representing frequencydependent capacitance and resistance of AFM tip and air, 5,13 and R inst is resistance of the instrument. Capacitance spectra of (a) HSV1 (▼) and mutated HSV1 adding green fluorescence proteins in capsid (▽) (b) HSV2 (○) and envelope-extracted HSV2 (•).…”

“…AC capacitance scanning probe microscopy (AC-SPM) was recently applied for characterization of various semiconductors and polymers with the spacial resolution in nanometers. [12][13][14] Recently, a nanoscale electrochemical probe was also demonstrated to probe electron transfers and ion flux mechanisms by penetrating cell membranes, 15 however biological samples at the nanoscale have not explored by this technique extensively. Many viruses have a structure consisting of an envelope as a shell, DNAs/RNAs in a core, and a capsid layer between the core and the envelope (Figure 1).…”