Negative Resistance State Research Articles

Theoretical and experimental study of the operation of ovonic switches in the relaxation oscillation mode. II. The discharging characteristics and the equivalent circuits

We describe that part of the relaxation oscillation cycle during which the ovonic device will switch from a high resistance OFF state to a lower conductance ON state, either as a time-varying resistance or through a nonlinear intermediate negative resistance state. We discuss in detail several equivalent circuits that describe the observed experimental behavior.

Electrical properties of TeAsGe films

The effect of temperature T, electrode separation d and substrate temperature T s on the I–V characteristics of amorphous films 3500 Å thick, vapour deposited from the alloy TeAsGe (53:36:11 at. %) onto a glass substrate at room temperature, were investigated. The material displayed the behaviour of a negative resistance device with a memory. The behaviour for T=constant is described by the relation V = CI exp (− αI), where C and α are constants for a specimen at constant temperature. The threshold voltage at which the off state transforms to the negative resistance state decreased with T according to the relation V th = V 0 exp ( E v /2 kT), where E v = 0.21 eV. V th increased with d and decreased with T s and was related to changes in resistance and structure. Microscope examination showed the formation of filaments containing recrystalized structure arising from Joule heating.

Memory and switching in semiconducting glasses: A review

Semiconducting glass diodes can exhibit several conducting states. A high resistance, or off state; a low resistance, or on state; a negative resistance state; and a memory on state have been reported. The data published on the laboratory operation of simple diodes and the methods of inducing transitions between the various states are reviewed. In addition, various suggestions which have been made to explain the mechanism of device operation are discussed.

The negative resistance anomaly in oscillatory photoconductivity

Computer experiments show that the total negative resistance state predicted for oscillatory photoconductivity is unstable in the presence of n + contacts under constant voltage conditions. Instead a non-uniform field distribution is established showing positive resistance.

Characteristics of Semiconducting Glass Switching/Memory Diodes

Semiconducting glass diodes can exhibit at least three conducting states: a high-resistance, or “off” state; a low-resistance, or “on” state; and a negative resistance state. When appropriately pulsed they can also display a memory function. The laboratory operation of simple diodes and the methods of inducing transitions among the various states are described. In addition, the possible role of phase changes in the mechanism of device operation is discussed, and new evidence in support of a filamentary conduction hypothesis is presented.

Negative resistance and high electric field capture rates in semiconductors

It is pointed out that the rate of capture of electrons and holes by charged centres should depend markedly on electric field strength when this is high enough to produce hot electrons. In particular, the capture rate for an attractive centre should decrease while the rate for a repulsive centre should increase as the field rises. Each effect will alter the steady state density of carriers. For the case of repulsive centres, a decrease in carrier density will occur and the possibility of using this phenomenon to produce a negative resistance state in the semiconductor is discussed. Suitably compensated n-type germanium crystals containing copper, nickel or gold appear to have the requisite properties for exhibiting negative resistance at temperatures low enough for the thermal ionization rate of the centre to be small. It is pointed out that the long time constants involved in the process preclude the use of short pulse fields.

The Dependence of Capture Rate on Electric Field and the Possibility of Negative Resistance in Semiconductors

It is pointed out that the rate of capture of electrons and holes by charged centres should depend markedly on electric field strength when this is high enough to produce hot electrons. In particular the capture rate for an attractive centre should decrease while the rate for a repulsive centre should increase as the field rises. Each effect will alter the steady state density of carriers. For the case of repulsive centres a decrease in carrier density will occur and the possibility of using this phenomenon to produce a negative resistance state in the semiconductor is discussed. Suitably compensated n-type germanium crystals containing copper, nickel or gold appear to have the requisite properties for exhibiting negative resistance at temperatures low enough for the thermal ionization rate of the centre to be small. It is pointed out that the long time constants involved in the process preclude the use of short pulse fields.