In this work we propose and analyze the possibility of creating terahertz plasmon-emitting graphene-channel transistor. It is shown that at electric pumping the damping of the terahertz plasmons can give way to their amplification, when the real part of the dynamic conductivity of graphene becomes negative in the terahertz range of frequencies due to the interband population inversion.
The present paper describes a new architecture of a high-voltage solid-state pulse generator. This generator combines the two types of energy storage systems: inductive and capacitive, and consequently operates two types of switches: opening and closing. For the opening switch, an isolated gate bipolar transistor (IGBT) was chosen due to its interesting characteristics in terms of controllability and robustness. For the closing switch, two solutions were tested: spark-gap (SG) for a powerful low-cost solution and avalanche mode bipolar junction transistor (BJT) for a fully semiconductor structure. The new architecture has several advantages: simple structure and driving system, high and stable controllable repetition rate that can reach 1 kHz, short rising time of a few nanoseconds, high gain and efficiency, and low cost. The paper starts with the mathematical analysis of the generator operation followed by numerical simulation of the device. Finally add a comma the results were confirmed by the experimental test with a prototype generator. Additionally, a comparative study was carried out for the classical SG versus the avalanche mode BJT working as a closing switch.
ISFET (Ion Sensitive Field Effect Transistors) microsensors are widely used for pH measurements as well as analytical and biomedical applications. At the same time, ISFET is a good candidate for testing various materials for their applications in sensitive membranes. For example, hydrogen sensitive carbonaceous films containing Pd nanocrystallites (C–Pd) make this material very interesting for sensor applications. A cost effective silicon technology was selected to fabricate n-channel transistors. The structures were coupled to specially designed double-sided PCB (Printed Circuit Board) holder. The holder enables assembly of the structure as part of an automatic stand. The last step of production of MIS structures was deposition of the C–Pd layer. The C–Pd films were fabricated by the Physical Vapor Deposition (PVD) method in which C60 and palladium acetate were evaporated. Electrical resistance of structures with C–Pd films was measured during their interaction with hydrogen. Finally, a new type of highly sensitive FET hydrogen sensor with C–Pd layer was demonstrated and characterized.
The behavioural model of a graphene field-effect transistor (GFET) is proposed. In this approach the GFET element is treated as a “black box” with only external terminals available and without considering the physical phenomena directly. The presented circuit model was constructed to reflect steady-state characteristics taking also into account GFET capacitances. The authors’ model is defined by a relatively small number of equations which are not nested and all the parameters can be easily extracted. It was demonstrated that the proposed model allows to simulate the steady-state characteristics with the accuracy approximately as high as in the case of the physical model. The presented compact GFET model can be used for circuit or system-level simulations in the future.
The paper presents a new electromechanical amplifying device i.e., an electromechanical biological transistor. This device is located in the outer hair cell (OHC), and constitutes a part of the Cochlear amplifier. The physical principle of operation of this new amplifying device is based on the phenomenon of forward mechanoelectrical transduction that occurs in the OHC's stereocilia. Operation of this device is similar to that of classical electronic Field Effect Transistor (FET). In the considered electromechanical transistor the input signal is a mechanical (acoustic) signal. Whereas the output signal is an electric signal. It has been shown that the proposed electromechanical transistor can play a role of the active electromechanical controlled element that has the ability to amplify the power of input AC signals. The power required to amplify the input signals is extracted from a battery of DC voltage. In the considered electromechanical transistor, that operates in the amplifier circuit, mechanical input signal controls the flow of electric energy in the output circuit, from a battery of DC voltage to the load resistance. Small signal equivalent electrical circuit of the electromechanical transistor is developed. Numerical values of the electrical parameters of the equivalent circuit were evaluated. The range, which covers the levels of input signals (force and velocity) and output signals (voltage, current) was determined. The obtained data are consistent with physiological data. Exemplary numerical values of currents, voltages, forces, vibrational velocities and power gain (for the assumed input power levels below 1 picowatt (10-12 W)), were given. This new electromechanical active device (transistor) can be responsible for power amplification in the cochlear amplifier in the inner ear.
We propose a novel magnetic field sensitive semiconductor device, viz., Horizontally-Split-Drain Magnetic-Field Sensitive Field-Effect Transistor (HSDMAGFET) which can be used to measure or detect steady or variable magnetic fields. Operating principle of the transistor is based on one of the galvanomagnetic phenomena and a Gradual Channel Detachment Effect (GCDE) and is very similar to that of Popovic and Baltes's SDMAGFET. The predicted absolute sensitivity of the new sensor can reach as high value as 1000 V/T. Furthermore, due to its original structure, the spatial resolution of the new MAGFET is very high which makes this device especially useful in reading magnetically encoded data or magnetic pattern recognition.
The paper presents a low noise voltage FET amplifier for low frequency noise measurements. It was built using two stages of an op amp transimpedance amplifier. To reduce voltage noise, eight-paralleled low noise discrete JFETs were used in the first stage. The designed amplifier was then compared to commercial ones. Its measured value of voltage noise spectral density is around 24 nV/√ Hz, 3 nV/√ Hz, 0.95 nV/√Hz and 0.6 nV/√ Hz at the frequency of 0.1, 1, 10 and 100 Hz, respectively. A −3 dB frequency response is from ∼ 20 mHz to ∼ 600 kHz.
DC-DC converters are popular switch-mode electronic circuits used in power supply systems of many electronic devices. Designing such converters requires reliable computation methods and models of components contained in these converters, allowing for accurate and fast computations of their characteristics. In the paper, a new averaged model of a diodetransistor switch containing an IGBT is proposed. The form of the developed model is presented. Its accuracy is verified by comparing the computed characteristics of the boost converter with the characteristics computed in SPICE using a transient analysis and literature models of a diode and an IGBT. The obtained results of computations proved the usefulness of the proposed model.