N-shaped negative differential resistance in a transistor structure with a resistive gate

1994 ◽  
Vol 41 (8) ◽  
pp. 1327-1333 ◽  
Author(s):  
Houng-Chi Wei ◽  
Yeong-Her Wang ◽  
Mau-Phon Houng
2021 ◽  
Vol 22 (2) ◽  
pp. 224-232
Author(s):  
A.V. Osadchuk ◽  
V.S. Osadchuk ◽  
I.A. Osadchuk ◽  
D.R. Ilchuk ◽  
G.A. Pastushenko

The paper presents a study of a solid state radio-measuring optical-frequency transducer of gas consumption based on a transistor structure with a negative differential resistance. A mathematical model of a solid state radio-measuring optical-frequency flowmeter was developed, which made it possible to obtain the conversion function and the sensitivity equation. The solid state radio-measuring optical-frequency gas flowmeter is based on a transistor structure with a negative differential resistance, consisting of a HEMT field-effect transistor and a bipolar transistor with a passive inductive element. When replacing the passive inductance with an active inductive element, the transducer can be completely integrated. The negative differential resistance formed by the parallel connection of the impedance with the capacitive component on the collector-drain electrodes of the transistor structure and inductance leads to the occurrence of electrical oscillations in the oscillator circuit. Theoretical and experimental studies have shown that with an increase in gas consumption from 0 l/h to 4 l/h, the generation frequency decreases from 812.65 MHz to 811.62 MHz at a supply voltage of 3.3 V, and at a supply voltage of 3.8 V from 813.00 MHz to 811.80 MHz. It is shown that by choosing a constant voltage power supply mode, it is possible to obtain an almost linear dependence of the generation frequency on the gas flow rate and choose channels for transmitting measurement information. The obtained theoretical and experimental studies are in good agreement, the relative error does not exceed 2.5 %.


Author(s):  
Alexander Osadchuk ◽  
Neonila Osadchuk ◽  
Jaroslav Osadchuk

The article discusses a radiomeasuring gas concentration transducer for the diagnosis of strains of the bacterium Helicobacter pylori. One of the promising directions in the construction of gas concentration transducers for respiratory diagnostics is the use of gas concentration frequency transducers based on the reactive properties of transistor structures with negative differential resistance (NDR). This type of transducers allows you to solve the problem of using analog-to-digital converters, because it implements the method of converting "informative signal - frequency", which is one of the best for further processing on a computer. Theoretical and practical studies have shown that using the reactive properties of semiconductor devices and transistor structures in which there is a negative differential resistance, it is possible to significantly increase the sensitivity and accuracy of measuring gas concentration, in particular NH3. The authors proposed and studied a gas concentration measuring transducer, which is built on the basis of a transistor structure with negative differential resistance and a gas-sensitive element to NH3. With a change in gas concentration, the conductivity of the sensitive element changes, which adsorbs NH3 molecules, which in turn changes the active and reactive components of the impedance of the transistors structure. The reactive component of the impedance of the transistors structure is capacitive in nature. This capacitance is part of the total capacitance that occurs at the electrodes of the drain of a double-gate MOS transistor and collector of a bipolar transistor, which together with the inductance L form a resonant oscillatory circuit. A dynamic mathematical model of the frequency transducer of gas concentration by the method of variable states is developed. The dynamic model of the self-generating secondary transducer of gas concentration allows you to determine the value of the frequency of the output signal depending on the change in gas concentration at any time. Analytical expressions of the transformation function and sensitivity equations are obtained. The sensitivity of the developed device for the diagnosis of strains of the bacterium Helicobacter pylori ranges from 2.1 kHz/ppm to 3.4 kHz/ppm.


2020 ◽  
Author(s):  
SMITA GAJANAN NAIK ◽  
Mohammad Hussain Kasim Rabinal

Electrical memory switching effect has received a great interest to develop emerging memory technology such as memristors. The high density, fast response, multi-bit storage and low power consumption are their...


2002 ◽  
Vol 25 (3) ◽  
pp. 233-237
Author(s):  
K. F. Yarn

First observation of switching behavior is reported in GaAs metal-insulator-p-n+structure, where the thin insulator is grown at low temperature by a liquid phase chemical-enhanced oxide (LPECO) with a thickness of 100 Å. A significant S-shaped negative differential resistance (NDR) is shown to occur that originates from the regenerative feedback in a tunnel metal/insulator/semiconductor (MIS) interface andp-n+junction. The influence of epitaxial doping concentration on the switching and holding voltages is investigated. The switching voltages are found to be decreased when increasing the epitaxial doping concentration, while the holding voltages are almost kept constant. A high turn-off/turn-on resistance ratio up to105has been obtained.


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