Different Values Of Bias Voltage Research Articles

Temperature dependence of interface state density distribution determined from conductance–frequency measurements in Ni/n-GaP/Al diode

The conductance measurements of the non-annealed (D1) and 400 °C annealed (D2) Ni/n-GaP/Al diodes were made over a wide frequency range of (10 kHz to 5 MHz) and temperature of (100–320 K with steps of 20 K) with bias voltage as a parameter. The capacitance and conductance measurement method is one of the most popular non-destructive methods to obtain information about metal–semiconductor (MS) diode interfaces. The interface state density distribution curves were determined over the band-gap energy near the semiconductor energy midgap. The interface state density (Dit) has been seen to be of the order of ∼1012 eV−1 cm−2. The Dit∼T curves have been plotted for different values of bias voltage. The value of Dit increased with increasing measurement temperature, and with increasing voltage from negative bias to positive bias voltage for both diodes. It was seen that the Dit value for D2 diode was greater than that for the D1 diode at each measurement temperature and bias voltage. It was seen in the interface state energy distribution or density distribution curves that the value of Dit has increased from the valence band maximum (Ev) towards conduction band minimum (Ec) at each measurement temperature.

Spin susceptibilities of doped bilayer graphene in the presence of magnetic ordering

We study the dynamical spin susceptibilities of biased bilayer graphene due to spin polarization effects in the context of tight binding model Hamiltonian. Green's function approach has been implemented to find the behavior of dynamical spin susceptibility of bilayer graphene within linear response theory. We have found the frequency dependence of imaginary part of spin susceptibilities for different values of bias voltage. Also the dependence of both transverse and longitudinal spin susceptibilities on spin polarization has been investigated in details. The frequency position of sharp peaks in the frequency dependence of the susceptibilities introduce the collective magnetic excitation modes of itinerant electrons on bilayer system.

Investigation of Transport Parameters of Graphene-Based Nanostructures

The paper presents results of computer simulation of the main transport parameters of nanostructures obtained through the row-by-row removal of carbon atoms from graphene ribbon. Research into the electrical parameters is carried out within the density functional theory using the non-equilibrium Green functions in the local-density approximation. Virtual NanoLab based on Atomistix ToolKit is used to construct structures and analyze simulation results. Current-voltage characteristics, differential conductivity and transmittance spectra of nanostructures are calculated at different values of bias voltage. It is found that there is a large region of negative differential resistance in current-voltage characteristics of nanostructures caused by resonant tunneling of quasi-particles. Differential (dI/dV) characteristic also has similar changes. The obtained results can be useful for building novel electronic devices in the field of nanoelectronics.

Bifurcation analysis of an electro-statically actuated micro-beam in the presence of centrifugal forces

In this paper, the influence of centrifugal forces on the stability of an electro-statically actuated clamped–clamped micro-beam has been investigated. The non-dimensional governing static and dynamic equations have been linearized using the step by step linearization method (SSLM), then, a Galerkin-based reduced order model has been used to solve the linearized equations. For constant value of a bias DC voltage and different values of angular velocity the equilibrium points of the corresponding autonomous system including stable center points, unstable saddle points and singular points have been obtained using the equivalent mass-spring model. Subsequently the bifurcation diagram has been depicted using the obtained fixed point. The static pull-in voltage value for different values of angular velocity and the static pull-in angular velocity for different values of bias voltage have been calculated. The obtained results are validated using results of previous studies and a good agreement has been observed. The effect of the centrifugal force on the fixed points has been studied using the phase portraits of the system for different initial conditions. Moreover, the effects of centrifugal forces on the dynamic pull-in behavior have been investigated using time histories and phase portraits for different angular velocities.

WE‐C‐L100J‐08: Charge Trapping in a Prototype Active Matrix Flat Panel Dosimeter and Its Implications

Purpose: This work models charge trapping behavior of a prototype Active Matrix Flat Panel Dosimeter (AMFPD) using three parameters and explains a number of published observations. An understanding of charge trapping and release is necessary to estimate non‐linearities in the AMFPD response due to trapping and to correct artifacts in the resulting dose image. Method and Materials: The AMFPD consisted of an amorphous silicon flat panel imaging array operated without a phosphor screen. Fluoroscopic and radiographic modes were used to obtain a series of fixed field dosimetric measurements at different doses and dose rates. Data were acquired in order to test the assumptions upon which the model was based:(1) Trapped charge density in the metastable defects can be described by a stretched exponential function, .(2) Trapped charge starts to release from the trapping centers when the photodiode is recharged.(3) Charge release is not affected by subsequent irradiations when the dose per frame is small.(4) The charge trapping rate depends on bias voltage and varies slowly with dose when the dose is small.Model stretch parameter β, time constant τ, and the charge trapping rate p were determined from a fit to the pixel signal decay following irradiation. These parameters were then applied to simulate results for the AMFPD operated in fluoroscopic mode based on the above assumptions. Results: The simulated results agreed well with the measurements. It was determined that β is constant for a detector array, τ depends on bias voltage, and the charge trapping rate depends on bias voltage and dose. Furthermore, the model qualitatively explains observations reported in published papers on charge trapping. Conclusion: A three parameter model was found to successfully describe the behavior of charge trapping and release at different values of bias voltage, frame rate, dose rate and dose.

Charge transport in low angle grain boundaries in germanium

Experimental measurements of charge transport within the plane of 1− and 4−deg grain boundaries in n-type germanium have been made. The grain boundary conductance parallel and perpendicular to the dislocations has been measured between liquid helium and room temperatures and for different values of bias voltage applied to the boundary. The experimental results show a marked anisotropy in the conductance in the grain boundary plane and an unexpected strong dependence of conductance on bias voltage.