arXiv subjects

Gennadi Bersuker

Publications and source records attributed to Gennadi Bersuker.

5 recordsLinked to original sources

arXiv2026

Mesoscopic Modeling of Structure-Transport Relationships in Dense CNT Films Containing Amorphous Carbon

Carbon nanotube (CNT) films are widely considered as prospective building blocks for advanced electronic and nanostructured materials. In particular, electrical transport in high-density CNT films results from a complex interplay between network morphology and CNT connectivity, which remains challenging to characterize quantitatively. To identify the structural parameters that govern the electrical current in CNT films, we employed coarse-grained molecular dynamics to construct dense mesoscale CNT film models that include CNTs with different chiralities and lengths. The effects of CNT geometrical features on the film morphologies were quantified by devising a set of structural descriptors and analyzing their mutual correlations. The impact of varying the concentration of amorphous carbon (aC) inclusions on the film structure was assessed. Finally, we employed a nodal analysis framework to compute the electrical current across the networks and correlate the charge transport characteristics to the underlying structural descriptors. The current is found to be enhanced in films that exhibit high curvature and buckling, low bundling, and strong connectivity. We discuss how the presence of aC inclusions modifies these morphological and current characteristics. This work provides a mesoscale modeling framework for modeling structure-transport relationships in dense CNT films and highlights the role of morphological descriptors in guiding the interpretation of electrical transport in complex nanostructured networks.

physics.comp-ph↗

arXiv2026

Strong radial electric field scaling near nanoscale conductive filaments and the ReRAM resistive switching mechanism

The physics underlying reset in bipolar resistive memory has been the subject of decades of controversy and has been identified as the primary barrier to resistive memory technology development. This manuscript introduces a nanoscale effect in current carrying conductors, whereby surface charge induced radial electric fields are found to be inversely proportional to the radius of the conductive path. This nanoscale effect is then applied to explain the negative resistance switching (reset) mechanism in filamentary metal oxide resistive switching memory devices (memristors). Previous explanations for the negative resistive switching mechanism state that diffusion constitutes the radial driving mechanism for oxygen ions, and drift under electric fields is restricted to the direction parallel to current flow. This explanation conflicts with retention and microscopy data collected in a subset of devices presented in literature. We demonstrate that the electric field's dependency on the on the radius of a nanoscale conductive path can result in radial fields on the order of 10^5 to 10^6 V/cm at only -1 V bias, sufficient to govern the negative resistance switching mechanism in filamentary metal oxides. By accounting for this nanoscale size effect, long standing anomalous experimental data about the negative (reset) resistance switching mechanism in bipolar filamentary resistive memory devices is finally reconciled. Wide understanding of surface charges and associated electric fields in nanoscale conductive paths could prove important for further scaling of integrated circuits and aid in elucidating many nanoscale phenomena.

cond-mat.mes-hall↗

arXiv2022

Observation of Fundamental Limit of Light Localization

In disordered media light can be localized in the spaces between scattering sites which average to an optical mean free path (MFP). However the fundamental question of the smallest MFP that can support Anderson localization of light remains unanswered due to fabrication complexity of a scattering medium with controlled nano-scale gaps and lack of required resolution by far-field methods. Here we use scanning probe microscopy technique to collect localized light created at gaps between scattering crystallographic defects in a large variety set of nano-gap III-V medium. No localized spots correlated to MFP below ~14.5 nm is observed at second-harmonic collection at 390 nm. Experiment and simulation resulted in the first direct observation of suppression of Anderson light localization correlated to ~13 nm optical MFP that reveals a fundamental constraint in electromagnetism and photonics.

physics.optics↗

arXiv2020

Atomic-Scale Defect Detection by Nonlinear Light Scattering and Localization

Hetero-epitaxial crystalline films underlie many electronic and optical technologies but are prone to forming defects at their hetero-interfaces. Atomic-scale defects such as threading dislocations that propagate into a film impede the flow of charge carriers and light degrading electrical-optical performance of devices. Diagnosis of subsurface defects traditionally requires time consuming invasive techniques such as cross sectional transmission electron microscopy. Using III-V films grown on Si, we have demonstrated noninvasive, bench-top diagnosis of sub-surface defects by optical second-harmonic scanning probe microscope. We observed a high-contrast pattern of sub-wavelength hot spots caused by scattering and localization of fundamental light by defect scattering sites. Size of these observed hotspots are strongly correlated to the density of dislocation defects. Our results not only demonstrate a global and versatile method for diagnosing sub-surface scattering sites but uniquely elucidate optical properties of disordered media. An extension to third harmonics would enable irregularities detection in non-X(2) materials making the technique universally applicable.

physics.app-ph↗

arXiv2010

Intrinsic Reliability improvement in Biaxially Strained SiGe p-MOSFETs

In this letter we not only show improvement in the performance but also in the reliability of 30nm thick biaxially strained SiGe (20%Ge) channel on Si p-MOSFETs. Compared to Si channel, strained SiGe channel allows larger hole mobility (μh) in the transport direction and alleviates charge flow towards the gate oxide. μh enhancement by 40% in SiGe and 100% in Si-cap SiGe is observed compared to the Si hole universal mobility. A ~40% reduction in NBTI degradation, gate leakage and flicker noise (1/f) is observed which is attributed to a 4% increase in the hole-oxide barrier height (ϕ) in SiGe. Similar field acceleration factor (Γ) for threshold voltage shift (ΔVT) and increase in noise (ΔSVG) in Si and SiGe suggests identical degradation mechanisms.

cond-mat.mes-hall↗