Papers by Alexander N Reznik
Observation of Magentoinductive Waves in Metamaterials
We develop the theory and study experimentally the propagation of linear magnetoinductive waves i... more We develop the theory and study experimentally the propagation of linear magnetoinductive waves in composite metamaterials. We present results of the first experimental observation of magnetoinductive waves in one-dimensional arrays of resonators.
Near-field microwave probing of a spherical object
2010 URSI International Symposium on Electromagnetic Theory, 2010
We have developed a theory for near-field (NF) sounding of a sphere located in a homogeneous medi... more We have developed a theory for near-field (NF) sounding of a sphere located in a homogeneous medium. We have considered the NF probe as an antenna with small aperture size D≪λ, where λ is the wavelength. The developed algorithm provides calculation of antenna impedance as a function of sphere diameter ds and antenna-to-object separation h. Our theory is based on the obtained solution of the diffraction problem for a sphere irradiated by the antenna near field. We have investigated quantitatively the excitation of electrical and magnetic multipoles in the sphere. Governing parameters of the electrodynamic system are ds/D and h/D. We have found the number of multipoles that should be taken into account for system characterization with given accuracy. The exact condition has been obtained for the applicability of the small-particle (Rayleigh) approximation. The excitation of multipole resonances has been revealed. We have used the developed theory to study the detectability of tumors i...
Bulletin of the Russian Academy of Sciences: Physics, 2012
A technique for the profiling of free carrier concentration N(z) in semiconductors, based on the ... more A technique for the profiling of free carrier concentration N(z) in semiconductors, based on the near-field measurements in microwave frequency range, is proposed. A high accuracy in retrieving the N(z) function with characteristic spatial scales of 10–100 nm using 2–3 probes with apertures of 3–15 μm is demonstrated.
The Review of scientific instruments, 2008
We have experimentally verified a recently proposed theoretical model for near-field microwave mi... more We have experimentally verified a recently proposed theoretical model for near-field microwave microscopy of multilayer media. The model addresses a near-field microwave probe as an electrically small antenna with a Gaussian-like current distribution that has a single characteristic length scale on the order of the probe size. Electrodynamic response of an antenna is calculated using Green functions in the form of integral transforms for electric and magnetic fields (both quasistatic and propagating), which are generated by a pointlike dipole. Experimental data were obtained at 4 GHz using a near-field scanning microwave microscope with aperture size of approximately 5 microm for a set of six SiO(2) films with thickness ranging from 0.1 to 1.5 microm. For each sample the probe resonant frequency was both measured and simulated as a function of the tip-sample distance, and good agreement between the theory and experimental data was observed. It was found that the model is capable of ...
Journal of Applied Physics, 2017
A scanning near-field microwave microscope (SNMM) was used to study resistance Rsh of a boron del... more A scanning near-field microwave microscope (SNMM) was used to study resistance Rsh of a boron delta-doped epilayer of diamond grown on a high pressure and high temperature substrate. Measurements were performed with an ∼1.4 GHz working frequency and an ∼85 μm space resolution microscope on samples with a lateral dimension of 3 × 3 mm2. Some substrates featured a crystalline structure defect over which the epilayer resistance Rsh was seen to increase by more than an order of ∼1 mm linear dimensions of the high-ohmic region. The SNMM measurement data revealed some substrates to have nonuniform conductivity, i.e., a high-ohmic area in the central part surrounded by a conducting edge region. In the latter case, the SNMM method allowed determining a surface distribution of epilayer resistance Rsh, undistorted by the shunting influence of the substrate. The reliability of the SNMM results is confirmed by the local four-probe resistance measurements. At the same time, the alternative metho...
Bulletin of the Russian Academy of Sciences: Physics, 2009
A theory for near-field microwave microscopy of plane-layered structures has been developed. The ... more A theory for near-field microwave microscopy of plane-layered structures has been developed. The probe of a near-field microscope is considered as electrically small antenna, which emits quasi-static fields and waves in a medium with an arbitrary 1D permittivity profile. The accuracy of the theory has been demonstrated by microscopy of thin dielectric films deposited on a conductive substrate. The possibility of determining film permittivity with an error of 5–7% is shown.
Journal of Applied Physics, 2016
We have developed an analytical model of a near-field microwave microscope based on a coaxial res... more We have developed an analytical model of a near-field microwave microscope based on a coaxial resonator with a sharpened tip probe. The probe interacts with a layered sample that features an arbitrary depth distribution of permittivity. The microscopic tip end with the accumulated charge is regarded as a monopole antenna radiating an electric field in near zone. The impedance of such an antenna is determined within a quasi-static approximation. The proposed model is used for calculating the sample-sensitive parameters of the microscope, specifically, resonance frequency f0 and quality factor Q0, as a function of probe-sample distance h. The theory has been verified experimentally in studies of semiconductor structures, both bulk and thin films. For measurements, we built a ∼2.1 GHz microscope with an effective tip radius of about 100 μm. The theoretical and experimental dependences f0(h) and Q0(h) were found to be in a good agreement. The developed theory underlies the method for de...
Journal of Applied Physics, 2017
A method for determining the parameters of a layered semiconductor structure, using the data obta... more A method for determining the parameters of a layered semiconductor structure, using the data obtained by near-field microwave probing with a micron-size lateral resolution, was developed and tested experimentally. We have measured a frequency spectrum of the impedance of a coaxial antenna formed on a test structure surface. The corresponding inverse problem has been solved based on the quasistatic theory for the impedance of a monopole antenna interacting with a layered medium, which was proposed earlier [A. N. Reznik and S. A. Korolyov, J. Appl. Phys. 119, 094504 (2016)]. This method was applied to a low-barrier Mott diode structure with a nearly 100 nm thick undoped layer grown on a conducting substrate GaAs. Computer simulation allowed us to establish the optimal frequency intervals and estimate the accuracy of determining the structure parameters. Measurements were taken in the frequency range of 0.1–67 GHz on commercially available equipment. Three antennas with a radius of the...
Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques, 2014
A method is proposed for determining the sheet resistance of a semiconductor film on a dielectric... more A method is proposed for determining the sheet resistance of a semiconductor film on a dielectric substrate with the help of a near-field (NF) microwave microscope. The method is based on the theory of NF probing of the object with an arbitrary 1D permittivity profile. The theoretical model parameters are found from calibration measurements performed with the use of a universal set of reference samples. The test structures are GaN films grown on an Al2O3 substrate. A comparison with dc measurements indicates that the method error is approximately 20%.
Journal of Applied Physics, 2013
We propose and experimentally approve a method for determining the sheet resistance Rsh of a semi... more We propose and experimentally approve a method for determining the sheet resistance Rsh of a semiconducting film on a dielectric substrate from the near-field (NF) microwave measurements data. The method is based on the earlier developed theory for NF microscopy of plane layered media. The fitting parameters of the theoretical model were sought using a universal set of calibration standards, specifically, bulk-homogeneous Si slabs varying in the doping degree. Experimental investigations were assisted by a 3 GHz resonance probe with an aperture of about 1 mm. As test structures we used n-GaN films of 0.03–15 kΩ sheet resistance, grown on a sapphire substrate. The accuracy of the technique was assessed by comparing the NF probing data with the dc measurements of Rsh in the Van-der-Pauw (VDP) method. For Rsh < 4 kΩ the root-mean-square deviation of NF from VDP data is approximately equal to 20%.
Technical Physics, 2020
Abstract The previously proposed technique of microwave volt–impedance spectroscopy of semiconduc... more Abstract The previously proposed technique of microwave volt–impedance spectroscopy of semiconductors has been experimentally verified. The technique allows one to determine the local values of electrical parameters of a semiconductor. The investigations have been carried out on a homogeneous single-crystal GaAs wafer with a system of concentric antennas formed on the top of it. The resolution is determined by the antenna central disk diameter, which has been 12, 27, and 57 μm. A dc bias voltage of 0 V ≤ U ≤ 5 V has been applied between antenna contact pads. The complex Z ( f , U ) impedance spectrum of each antenna has been measured on a Cascade Microtech probe station in the frequency range of f = 0.1–10 GHz. The electrical characteristics of the semiconductor have been determined from the Z ( f , U ) spectra by solving the inverse problem. The n -type of the semiconductor has been established, and the contact potential difference at the interface with a metal has been determined. The local values of electron density, mobility and electrical conductivity have been found have been found. The four-point probe Hall effect measurements of the surface-averaged values of the same parameters have shown good agreement of the results for the investigated homogeneous wafer.
Technique for determination of RF-magnetic field dependence of the HTS surface impedance by microwave resonators
MMET Conference Proceedings. 1998 International Conference on Mathematical Methods in Electromagnetic Theory. MMET 98 (Cat. No.98EX114)
ABSTRACT
Journal of Applied Physics, 2017
A method for determining the parameters of a layered semiconductor structure, using the data obta... more A method for determining the parameters of a layered semiconductor structure, using the data obtained by near-field microwave probing with a micron-size lateral resolution, was developed and tested experimentally. We have measured a frequency spectrum of the impedance of a coaxial antenna formed on a test structure surface. The corresponding inverse problem has been solved based on the quasistatic theory for the impedance of a monopole antenna interacting with a layered medium, which was proposed earlier [A. N. Reznik and S. A. Korolyov, J. Appl. Phys. 119, 094504 (2016)]. This method was applied to a low-barrier Mott diode structure with a nearly 100 nm thick undoped layer grown on a conducting substrate GaAs. Computer simulation allowed us to establish the optimal frequency intervals and estimate the accuracy of determining the structure parameters. Measurements were taken in the frequency range of 0.1–67 GHz on commercially available equipment. Three antennas with a radius of the...
Instruments and Experimental Techniques, 2018
The design and operation principles of a magnetic resonance force microscope (MRFM) that has been... more The design and operation principles of a magnetic resonance force microscope (MRFM) that has been developed on the basis of the Solver HV vacuum scanning probe microscope are described. This device is intended to study local microwave properties of ferromagnetic micro-and nanostructures in the frequency range of 0.1-20 GHz and in an external magnetic field as high as 0.35 T.
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Papers by Alexander N Reznik