G.L. Bleris

DISTRIBUTION OF LAMINAR LENGTHS FOR NOISY ON-OFF INTERMITTENCY

Abstract A universal distribution of laminar lengths for the noisy on-off intermittency is obtained analytically. The distribution is well approximated by a power law with an exponent −3 2 for moderate laminar lengths and an exponential law describing fast falloff for large laminar lengths. The shoulder region, observed in previous numerical studies, is described by the same exponential law as the region of fast falloff.

Analysis of microhardness data in TlxIn1−xSe

Microhardness measurements have been performed on TlxIn1−xSe semiconductors (x=0.0, 0.2, 0.3 ... 1.0). The microhardness, H, as a function of x shows a maximum at x ca. 0.5. A statistical evaluation of the obtained results leads to a log-normal distribution of the microhardness rather than, as expected, a polynomial one.

Intermittency in low frequency current oscillations in semi-insulating GaAs

Abstract Spontaneous low frequency current oscillations were observed in semi-insulating crystalline GaAs. If the value of the applied voltage U was increased, a crisis induced intermittency was observed. The time intervals between successive transitions were measured. For values of the control parameter U larger than a critical value two interacting chaotic subattractors were observed. The average time intervals are scaling with the control parameter with a critical exponent very close to −1/2.

High-frequency oscillations in an α-Si/Si(p)/Si(n) device

Abstract An α-Si/Si(p)/Si(n) heterojunction transistor exhibits current oscillations, which depending on the applied base–emitter voltage are either periodic or chaotic. The frequency dependence of the oscillations on the collector–emitter and the base–emitter voltage as well as on the load resistance, are presented.

Electrical properties of an a-Si/Si(p)/Si(n) heterojunction device

The electrical I-U characteristics of the three-terminal device a-Si/Si(p)/Si(n) have been investigated. The device shows both transistor and switching behaviour depending on the magnitude of the base current. The influence of the base current on the holding and switching voltages has been studied. A model describing this behaviour of the device has been suggested. It is based on the existence of a narrow region adjacent to the a-Si/Si(p) junction, characterized by an extremely high recombination rate of the injected carriers.

Current pulses and high-frequency oscillations in a-Si/Si(p)/Si(n) heterojunction device

A three-terminal a-Si/Si(p)/Si(n) heterojunction device was found to generate pulses of the collector current with a rise time of approximately 10-7 s and a fall time of approximately 4 ? 10-7 s. The voltage applied to the base (0.8-1.5 V) controlled the pulse repetition rate. When the voltage reaches ~1.0 V, the pulses start to overlap, and the output signal is a high-frequency oscillation (106-107 Hz) of the collector current. A simple mechanism explaining the pulse generation and the high-frequency oscillations has been proposed. It involves the extremely high recombination rate of the injected carriers in the thin a-Si layer of the a-Si/Si(p) interface.

DIFFUSIONAL MODEL FOR NOISY ON OFF INTERMITTENCY

Statistical properties of the laminar lengths for the noisy on–off intermittency are studied analytically. The universal distribution of the laminar phases is obtained at the critical point. It can be approximated by the power law with the exponent -3/2 and the exponential law describing fast falloff.