Negative Resistance Phenomenon Research Articles

Investigation of AlGaAs/GaAs superlattice-emitter resonant tunneling bipolar transistor (SE-RTBT)

A bipolar transistor with an i-Al/sub 0.5/Ga/sub 0.5/As/n/sup +/-GaAs superlattice emitter as both hole reflection barriers and electron tunneling barriers has been fabricated successfully. The AlGaAs/GaAs potential spike is eliminated by moving the heterointerface away from the emitter-base junction. Both the turn-on voltage of emitter-base and base-collector junctions are almost identical for the same current level. The room-temperature common-emitter current gain is over 60, and a collector-emitter offset voltage of 55 mV has been obtained with a base-to-emitter doping ratio of 10. Multiple differential negative resistance phenomena and different transistor operating regimes have been observed due to the tunneling effects in the AlGaAs/GaAs superlattice at 77 K. Calculated results are in agreement with experimental ones. Because of the existence of high peak-to-valley current ratios as well as current gain over 65, the SE-RTBT is suitable for multivalued logic circuit applications with relatively reduced complexity.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

感湿特性を有する感温磁性半導体を用いた多機能センサモジュール

The temperature-sensitive magnetic semiconductor (TMS) is a multi-ability sensor, with the functions of the thermistor and a thyratron-type bidirectional diode and the temperature-sensitive magnetic core. The TMS has the humidity dependence on the capacity and resistance which decreases with rising the humidity. The reluctance on the magnetic property with the temperature dependence is, independent of the humidity. The current-voltage characteristics show bidirectional non-linear negative resistance phenomena including three states; a cut off state, a negative resistance state and an “on” state. The application of the TMS for utilization as versatile temperature/humidity measurement module is shown.

Auger suppression and negative resistance in low gap PIN diode structures

PIN diodes made with narrow band-gap material dominated by Auger generation-recombination processes exhibit total Auger suppression in large reverse bias if the device length is below a critical value. Longer devices exhibit only partial Auger suppression. These effects are accompanied by strong negative resistance phenomena which result in high device impedances at high bias. These properties make low-gap PIN diodes important structures for low noise infrared detectors at moderate temperatures.

Mechanisms of the negative-resistance characteristics in AC thin-film electroluminescent devices

A model describing the mechanism responsible for generating the negative-resistance phenomenon found in hysteretic ZnS:Mn ACTFEL devices is presented. This model, which is based on simple physics intuitions rather than elaborate mathematical and numerical analyses, outlines several essential device parameters that are necessary to induce the negative-resistance effect.

Electrical properties of GeO2films

Measurements have been made on thin films using Ge${\mathrm{O}}_{2}$ as the dielectric material and for thickness ranges from 130 to 2000 \AA{}. These thin layers of Ge${\mathrm{O}}_{2}$ show a number of interesting electrical properties which include electroforming, voltage-controlled differential negative resistance, electroluminescence, electron-emission, and switching-memory effects. A theory is developed in terms of the growth and thermal rupture of many conducting filaments through the insulating layer to explain the observed voltage-controlled differential negative resistance, electron-emission, electroluminescence, and memory phenomena.

Study of electronic behavior of some semiconductors vanadate-arsenate glasses

The conduction mechanisms between 77° and 500°K of some glasses in the V 2O 5As 2O 3RO (R=Ba, Ca, Pb) systems, are discussed. A change of the slope in the electrical conductivity versus 1/T for a critical temperature was observed. The compositional effect, the network modifier ions influence and the apparent anomaly of the electrical conductivity and of the activation energy variation versus V 4+/V total ratio are also studied. The electrical and thermoelectrical data of these glasses indicates that such materials are in close agreement with a small-polaron conduction model. Finally the non-ohmic behaviour of negative resistance phenomena of thermistor-type produced by a local micro-heating due to a thermal effect Joule-Type are studied.

Semiconductors : critical exponents of the unijunction transistor transition

The negative resistance phenomenon in the unijunction transistor is interpreted as a phase transition, for which the critical exponents β, γ' and δ are measured. Far from the critical point, these exponents have classical values : β = 1/2, γ' = 1, δ = 3. Close to the critical point, β and γ' decrease to 0.2 and 0.2 respectively.

Book reviews

Abstract Europe's Giant Accelerator. By M. GOLDSMITH and E. SHAW. (Taylor and Francis, London, 1977.) [Pp. x+261.] £13·00. Electrical and Optical Properties of 111-V Semiconductors. By N. G. BASOV; translated by A. Tybulewicz. (Consultants Bureau, 1978.) [Pp. 118.] $39·00. Seope: Treatise. Level: Spccialist/postraduate. From Idea to Application : Some Selected Nuclear Techniques in Research and Development. (IAEA, Vienna, Proceodings of an Advisory Group Meeting at San José, Costa Rice, 1977. 1978.) [Pp. 301.] $23·00. Level: Postgraduate. États Atomiques et Moléculaires Coupés a un Continuum: Atomes et Molécules Hautement Excités (Colloquium No. 273, Aussois, June 1977). (CNRS, Paris, 1977.) [Pp. 361.1 135F. Scope: Interaction between radiation and highly excited atoms and molecules, Level: Research. Electron Spectroscopy for Surface Analysis. Edited by H. IBACR. (Springer-Verlag, 1977.) Tunnelling and Negative Resistance Phenomena in Semiconductors. By D. K. ROY (Editor 13. R: PAMPLIN). (Pcrgamon Press, 1977.) [Pp. xv+213.] $17·50. Scope: Monograph. Level. Final Honours/Postgraduate. Crystal Field Effects in Metals and Alloys. Edited by A. FURRER. (Plenum Press, 1977.) [Pp. xiv+365.]

Negative dynamic resistance in MOS devices

An electro thermal model is presented to explain negative dynamic resistance phenomena observed in the saturation region of MOS transistors operating at moderate and elevated power levels (P/SUB d//spl ges/300 mW).

A model for current-controlled negative resistance in ion/membrane systems

This work concerns chemical analogs of double injection semiconductors, and the phenomenon of negative resistance. Weber and Ford's semiconductor analysis is used extensively. Steady-state negative resistance curves are calculated for membranes with the following characteristics: (1) The membrane contains mobile anions and cations that experience ion-pairing; (2) The membrane possesses positive and negative bound charges; (3) The mobile ions and the bound charges react reversibly. The significance of these factors is discussed.

A model of switching and negative resistance phenomenon in organic thin film with dipoles

Thin films formed by organic molecules with dipoles may switch at a threshold voltage; the switching is due to the flip-flop of the dipoles. Theoretically derived equations agree well with the experiment.

Tunnelling and Negative Resistance Phenomena in Semiconductors

Tunnelling and Negative Resistance Phenomena in Semiconductors

One-frequency parametric amplifier using self-pumped Josephson junction

Gain and noise properties of a non-degenerate one-frequency parametric amplifier using a self-pumped Josephson junction are investigated both theoretically and experimentally. The amplifier uses the phenomenon of microwave negative resistance of the junction. Theoretical analysis made in usual resistively shunted junction (RSJ) model shows that the minimum noise temperature is equal to approximately 42T. It takes place at a signal frequency f close to the junction characteristic frequency f <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> . Maximum effectivity (the product of the square root of power gain and relative bandwidth) can reach 0.4 at f≃f <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> . Gain up to 20 dB was obtained at X-band using amplifier with Nb-Ta point-contact junction. Minimum noise temperature at T = 4.2K was about 200K.

Tomasch-effect-induced negative-resistance phenomena in single-crystal superconducting Pb films

A negative-resistance region has been observed just above the gap in tunnel junctions fabricated on 110&gt;-oriented single-crystal Pb films. This phenomenon was found to be present only when tunneling into single-crystal Pb films about 1.4 \ensuremath{\mu}m thick. When these junctions were raised to temperatures above 3.7\ifmmode^\circ\else\textdegree\fi{}K or placed in a parallel applied magnetic field above 200 G the negative resistance was not present although a deep minimum in conductance persisted. The structure was always accompanied by large Tomasch oscillations and appears to be related to the presence of the Tomasch effect and the details of the effect as they occur in 100&gt;-oriented single-crystal Pb films. The negative resistance and accompanying structure were reproduced in some respects by theoretical calculations using a superconductor density of states modified by the Tomasch term.

Spontaneous conductance changes, multilevel conductance states and negative differential resistance in oxidized cholesterol black lipid membranes.

Oxidized cholesterol lipid films were studied under voltage clamp conditions. Certain kinds of conductance phenomena closely resembling effects described in the literature and atributed to various additives were observed with unmodified lipid films. These include spontaneous conductance changes, multilevel conductance states and negative resistance phenomena in films formed from aged oxidized cholesterol-inhydrocarbon solutions. The multilevel conductance state manifests itself in the form of step changes in current under voltage clamp, the magnitudes of which correspond to conductance intervals of 5±2×10−10 mho and its multiples in 0.1n sodium chloride. These steps are attributed to channels that form in the film. Under certain conditions it has been observed that the action of the electric field was to close channels that were open at lower voltages. Under these conditions the current-voltage plot shows a distinct region of “negative differential” resistance. Films generated from freshly prepared oxidized cholesterol solutions did not exhibit multistable phenomena but under a prolonged voltage clamp the membrane conductance went into a transition from a stable, relatively noise-free-current state to a gradually increasing current with a large noise component. This sequence generally signalled imminent breakdown but the membrane could spontaneously revert to the original high-resistance, low-noise state. These kinds of intrinsic behavior sufficiently resemble certain effects produced by additives to merit special consideration during membrane reconstitution experiments.

Negative resistance phenomenon in a semiconductor with deep centres changed into traps by magneto-depletion effect

It is shown that injection of free carriers by the magneto-concentration effect in the predepleted region of a near intrinsic semiconductor slab with deep centres, gives rise to a negative resistance effect. It is proved theoretically and experimentally (by experiments of decaying photoconductivity) that this phenomenon is due to the increase of trapping of deep centres in the magnetodepleted region. This result leads to an interesting negative resistance device adjustable both by magnetic and electric fields. Nous mettons en évidence un effet de résistance négative, lors de l'injection de porteurs dans la zone préappauvrie en poteurs libres, par effect de magnétoconcentration, d'un barreau de semiconducteur quasi-intrinsèque doté de centres profonds. Nous montrons théoriquement et expérimentalcment (à l'aide d'expériences de photoconductivité), que ce phénoméne résulte de la transformation en pièges, par effet d'appauvrissement, des centres profonds. Nous disposons ainsi d'un dispositif à résistance négative, contrǒlable par champ magnétique et par champ électrique.

Double injection and electroluminescence in insulating GaSe and GaS 0.5Se 0.5 single crystals

We report here negative resistance phenomena with electroluminescent emission in insulating GaSe and GaS 0.5Se 0.5. Electroluminescent spectra show for GaSe crystals four levels, localized in the forbidden gap, which have a distance from the valence band of 0.1 eV, 0.25 eV, 0.35 eV, and 0.48 eV and four levels in the case of GaS 0.5Se 0.5 crystals at 0.53 eV, 0.63 eV, 0.74 eV, and 0.80 eV from the valence band. Electroluminescent emission is explained by double injection mechanism.

A model for filament growth and switching in amorphous oxide films

The forming process, by which changes are brought about in the electronic conduction of thin films of various binary amorphous oxides and halides, is first described, and experimental evidence is put forward which contradicts an earlier theory of the forming process in gold-silicon monoxide-metal structures. A theory is developed, in terms of the growth and thermal rupture of many conducting filaments through the insulating layer, to explain the observed voltage controlled negative resistance, electron emission, electroluminescence and memory phenomena. The model is presented firstly in its simplest phenomenological form, after which some atomic mechanisms which may be involved are tentatively discussed.It is further shown that there is evidence to suggest that the forming process in important in a wide range of systems. These include metal-oxide-silicon capacitors and transistors, surface-barrier junctions on silicon, oxide-coated thermionic cathodes and anodic oxide layers. Electronic conduction in each of these cases is held to take place through localized filamentary paths.The relationship between this and other filamentary conduction models is briefly discussed, and a general classification of negative-resistance devices into regenerative and non-regenerative systems is made.

Negative Resistance and Relaxation Effect of Conductivity in Photoconductive CdS at Low Temperature

Negative resistance phenomena are observed in CdS single crystal at temperatures below 222°K and at conductivities larger than 10-3(\\varOmega cm)-1. We are interested here in the change of conductivity σ(t) after sudden removal of the high electric field which caused the negative resistance. The relaxation time of conductivity is very long ranging from a few seconds to several tens seconds and varying linearly with the inverse of conductivity. The relaxation time versus 1/T curve has a kink point at 222°K; this temperature coincides with the critical temperature below which the negative resistance can be observed. From measurements of the spatial distribution of relaxation time and electric field it is found that the negative resistance is not caused by the inhomogeneity but by the decrease of the number of carriers in the sample.

Negative resistance in cadmium sulphide films

(I, V) characteristics of aluminium-cadmium-sulphide-aluminium (or indium) thin film structures have been studied. After an irreversible breakdown, the (I, V) curve shows an interesting dual negative resistance phenomenon. When the upper electrode is positive the curve first follows a low-conductivity path from which it switches over to a high-conductivity state through a current-controlled negative resistance. On decreasing the voltage, the high-conductivity path is maintained until a critical voltage in the opposite direction is reached when the structure switches back to the low-conductivity state through a voltage-controlled negative resistance region.