Trapping-detrapping processes in nanostructures are generally considered to be destabilizing factors. However, we discovered a positive role for a single trap in the registration and transformation of useful signal. We use switching kinetics of current fluctuations generated by a single trap in the dielectric of liquid-gated nanowire field effect transistors (FETs) as a basic principle for a novel highly sensitive approach to monitor the gate surface potential. An increase in Si nanowire FET sensitivity of 400% was demonstrated.

Abstract.Investigations of the phase transitions and self-organization in the magnetic aggregates are of the fundamental and applied interest. The long-range ordering structures described in the Tománek's systematization (M. Yoon, and D. Tománek, 2010 [1]) are not yet obtained in the direct molecular dynamics simulations. The resulted structures usually are the linear chains or circles, or, else, amorphous (liquid) formations. In the present work, it was shown, that the thermodynamically equilibrium primary ferrofluid aggregate has either the long-range ordered or liquid phase. Due to the unknown steric layer force and other model idealizations, the clear experimental verification of the real equilibrium phase is still required. The predicted long-range ordered (crystallized) phase produces the faceting shape of the primary ferrofluid aggregate, which can be recognized experimentally. The medical (antiviral) application of the crystallized aggregates has been suggested. Dynamic formation of all observed ferrofluid nanostructures conforms to the Tománek's systematization.

PACS 72. 70.+m, 73.40.Kp, 73.50.Td γ-ray radiation effect has been studied on transport and noise properties of high electron mobility transistors (HEMTs) with gate lengths in the range from 350 to 150 nm at room temperature. Current-voltage (I -V) characteristics of the devices demonstrate higher radiation hardness to 60 Co γ-rays up to doses of 10 9 Rad at larger gate lengths. This confirms the very important role of surface passivation for channel transport of the HEMTs. The deviation of the I -V characteristics parameters saturated current, transconductance, channel conductance, and threshold voltage does not exceed 20% at highest radiation dose. The noise spectra of pre-irradiated devices and after γ-irradiation show different frequency dependences corresponding to different fluctuation processes in the HEMTs. The results are confirmed by dynamic current measurements of the channel conductivity.

ABSTRACT. We employ noise spectroscopy and transconductance measurements to establish the optimal regimes of operation for our fabricated silicon nanowire field-effect transistors (Si NW FETs) sensors. A strong coupling between the liquid gate and back gate (the substrate) has been revealed and used for optimisation of signal-to-noise ratio in sub-threshold as well as abovethreshold regimes. Increasing the sensitivity of Si NW FET sensors above the detection limit has been predicted and proven by direct experimental measurements.

Abstract. We studied the noise spectra of molecule-free and molecule-containing mechanically controllable break junctions. Both types of junctions revealed typical 1/ f noise characteristics at different distances between the contacts with square dependence of current noise power spectral Ca, 87.15.hj, 85.65.+h.