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Krisztian Kordas

Publications and source records attributed to Krisztian Kordas.

3 recordsLinked to original sources

Resistive switching behaviors in vertically aligned MoS$_2$ films with Cu, Ag, and Au electrodes

Neuromorphic computing circuits can be realized using memristors based on low-dimensional materials enabling enhanced metal diffusion for resistive switching. Here, we investigate memristive properties of vertically aligned MoS$_2$ (VA-MoS$_2$) films with three different metal electrodes: Ag, Cu, and Au. Despite having the same active material, all three metals show distinct switching behavior, which are crucial for neuromorphic computing applications: Ag enables volatile switching, Cu demonstrates stable non-volatile switching with retention over 2500 s, and Au shows no memristive response. Cu devices show abrupt resistance changes, and significant increase of copper content upon biasing, indicative of stable non-volatile switching based on filament formation and rupture. About 85% of Ag and Cu devices exhibit reliable memristor behavior. Our findings provide valuable insights into the memristive switching mechanism in VA-MoS$_2$ and present a promising avenue for facile fabrication of neuromorphic circuits by employing a set of different metals on a single active material.

cond-mat.mes-hall↗

Viable route towards large-area two dimensional MoS2 using magnetron sputtering

Structural, interfacial, optical, and transport properties of large-area MoS2 ultra-thin films on BN-buffered silicon substrates fabricated using magnetron sputtering are investigated. A relatively simple growth strategy is demonstrated here that simultaneously promotes superior interfacial and bulk MoS2 properties. Few layers of MoS2 are established using X-ray reflectivity, diffraction, ellipsometry, and Raman spectroscopy measurements. Layer-specific modeling of optical constants shows very good agreement with first-principles calculations. Conductivity measurements reveal that few-layer MoS2 films are more conducting than many-layer films. Photo-conductivity measurements reveal that the sputter deposited MoS2 films compare favorably with other large-area methods. Our work illustrates that sputtering is a viable route for large-area device applications using transition metal dichalcogenides.

cond-mat.mtrl-sci↗

Compact USB measurement and analysis system for real-time fluctuation enhanced sensing

Measuring the resistance fluctuations of gas sensors provides new opportunities to enhance the selectivity and sensitivity of the sensor. Taking advantage of this possibility requires special low-noise measurement hardware and software to acquire data and perform analysis. In this paper we will present a small, USB-powered device capable of doing precise measurement of the resistance fluctuations of different kinds of gas sensors. We have developed a graphical user interface software to control the parameters of the measurement, to collect data and perform real time analysis on the measured data. The analysis is based on a PCA algorithm, which is proven to be a high performance tool to support fluctuation enhanced sensing. The system has been tested on Taguchi and carbon nanotube based gas sensors as well. The main advantages of the system include the small form factor, low cost and the fully featured software performing all required data analysis operations. Complemented with a gas sensor and an optional test chamber, the setup can serve as an efficient tool for practical fluctuation-enhanced gas sensing.

physics.ins-det↗