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Vladimir Protasenko

Publications and source records attributed to Vladimir Protasenko.

22 records · Page 2Linked to original sources

High-Voltage Field Effect Transistors with Wide-Bandgap β-Ga2O3 Nanomembranes

Nanoscale semiconductor materials have been extensively investigated as the channel materials of transistors for energy-efficient low-power logic switches to enable scaling to smaller dimensions. On the opposite end of transistor applications is power electronics for which transistors capable of switching very high voltages are necessary. Miniaturization of energy-efficient power switches can enable the integration with various electronic systems and lead to substantial boosts in energy efficiency. Nanotechnology is yet to have an impact in this arena. In this work, it is demonstrated that nanomembranes of the wide-bandgap semiconductor gallium oxide can be used as channels of transistors capable of switching high voltages, and at the same time can be integrated on any platform. The findings mark a step towards using lessons learnt in nanomaterials and nanotechnology to address a challenge that yet remains untouched by the field.

cond-mat.mes-hall↗

Transistors with Chemically Synthesized Layered Semiconductor WS2 Exhibiting 105 Room Temperature Modulation and Ambipolar Behavior

We report the realization of field-effect transistors (FETs) made with chemically- synthesized layered two dimensional (2D) crystal semiconductor WS2. The 2D Schottky-barrier FETs demonstrate ambipolar behavior and a high (~105x) on/off current ratio at room temperature with current saturation. The behavior is attributed to the presence of an energy bandgap in the 2D crystal material. The FETs show clear photo response to visible light. The promising electronic and optical characteristics of the devices combined with the layered 2D crystal flexibility make WS2 attractive for future electronic and optical devices.

cond-mat.mes-hall↗

Power Law Blinking Quantum Dots: Stochastic and Physical Models

We quantify nonergodic and aging behaviors of nanocrystals (or quantum dots) based on stochastic model. Ergodicity breaking is characterized based on time average intensity and time average correlation function, which remain random even in the limit of long measurement time. We argue that certain aspects of nonergodicity can be explained based on a modification of Onsager's diffusion model of an ion pair escaping neutralization. We explain how diffusion models generate nonergodic behavior, namely a simple mechanism is responsible for the breakdown of the standard assumption of statistical mechanics. Data analysis shows that distributions of on and off intervals in the nanocrystal blinking are almost identical, $ψ_{\pm}(τ)\propto A_{\pm}τ^{-(1+α_{\pm})}$ with $A_{+}\approx A_{-}$ and $α_{+}\approxα_{-}=α$ and $α\approx0.8$. The latter exponent indicates that a simple diffusion model with $α=0.5$ neglecting the electron-hole Coulomb interaction and/or tunneling, is not sufficient.

cond-mat.stat-mech↗