Low-frequency oscillations and routes to chaos in semi-insulating GaAs

Maracas, G. N.; Porod, Wolfgang; Johnson, David A.; Ferry, D. K.; Goronkin, H.

doi:10.1016/0378-4363(85)90355-9

Cited by 27 publications

(17 citation statements)

References 8 publications

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“…This observation contrasts with previous speculations, stating that the domain velocity scales with the free-carrier velocity reduced by the ratio of the low-field carrier concentration and the ionized traps no/Nt-. Although this conjecture gives the right order of magnitude for i)£>, and the dependence vq ~ no was confirmed by a number of other workers [9,22,15], the relation vq ~ 1 /Nt-is incompatible with our more detailed data. Figure 6 (lower panel) shows that N¡~ first increases and then decreases with domain size while the velocity increases steadily.…”

Section: Stable-domain Propagationcontrasting

confidence: 64%

Non-linear transport and structure formation in semi-insulating GaAs

Willing

Maan

1996

J. Phys.: Condens. Matter

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Abstract. We present an experimental study of slow domains in semi-insulating GaAs using time-resolved, two-dimensional electro-optic voltage probing. A detailed analysis of the shape of the bulk domains proves that they are formed by symmetric charge dipoles made up from ionized traps. The study of the dependence of the domain parameters on the applied voltage allows us for the first time to reconstruct experimentally the bulk y (^-characteristic of SI-GaAs and to show that prevailing theoretical models fail to explain the observations. The experimentally determined field dependence of the free-carrier concentration reveals a strongly field-enhanced trapping with no critical field. The drift velocity of domains is experimentally found to be exclusively determined by the free-carrier concentration at the centre of the domain.

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Section: Stable-domain Propagationcontrasting

confidence: 64%

Non-linear transport and structure formation in semi-insulating GaAs

Willing

Maan

1996

J. Phys.: Condens. Matter

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“…The steady-state properties of the transition from the low-conducting state to the high-conducting state have been analyzed in terms of nonequilibrium phase transformations [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. In the course of the transition, spontaneous oscillations and chaotic current fluctuations have been observed in several semiconductor materials 1,[5][6][7][8][9][10][11][12][13][14][15][16][17]. Different types of, and routes to, chaos were recognized and discussed in terms of nonlinear dynamics [18][19][20][21][22][23][24][25][26][27][28].…”

mentioning

confidence: 99%

“…Different types of, and routes to, chaos were recognized and discussed in terms of nonlinear dynamics [18][19][20][21][22][23][24][25][26][27][28]. Current fluctuations in semiconductors may occur spontaneously I- [5][6][7][8][9][10][11][12][13] or be induced by an external periodic driving force 1-13-17].…”

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confidence: 99%

Sequence of different types of nonlinear current oscillation in n-GaAs

1989

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Abstract. Self-generated chaotic current fluctuations in the post-breakdown regime of a n-GaAs layer at 4.2 K have been analyzed in detail. Without an external magnetic field only regular oscillations were observed. Increasing the magnetic field strength up to 100mT generates a sequence of quasiperiodic and frequency-locking current oscillations and finally a Ruelle-Takens-Newhouse scenario with chaos. This may be understood by assuming two coupled oscillatory processes caused by dielectric relaxation and energy relaxation in the distribution of free carriers. 05.40., 72.70., 72.20J High-purity semiconductors at low temperature show highly nonlinear current-voltage characteristics. For small electric fields almost all carriers are bound to shallow impurities yielding a low conductance of the sample. At a critical field of a few volts per cm the impact ionization rate of shallow impurities exceeds the capture rate for low carrier concentration resulting in a rapid increase of the current. The steady-state properties of the transition from the low-conducting state to the high-conducting state have been analyzed in terms of nonequilibrium phase transformations 1-14]. In the course of the transition, spontaneous oscillations and chaotic current fluctuations have been observed in several semiconductor materials 1,5-17]. Different types of, and routes to, chaos were recognized and discussed in terms of nonlinear dynamics [18][19][20][21][22][23][24][25][26][27][28]. Current fluctuations in semiconductors may occur spontaneously I-5-13] or be induced by an external periodic driving force 1-13-17]. PACS:In the present paper we report on a detailed study of self-generated current fluctuations in high purity n-GaAs epitaxial layers which occur within a limited bias voltage interval in the post-breakdown regime of the material. The observed phenomena depend critically on the strength of an external magnetic field. At zero field, B = 0, only regular oscillations were found. Increasing B up to not more than 100mT causes a sequence of quasiperiodic and frequency-locking current phenomena, finally undergoing a Ruelle-TakensNewhouse scenario to chaos. This behavior may be attributed to the coupling of two oscillatory processes, in the present case dielectric relaxation and an oscillation of the nonequilibrium electron distribution. The experimental results are in excellent agreement with the predictions of the circle-map theory. The coupling strength, frequencies and amplitudes of both selfsustained processes depend strongly on the magnetic field strength.

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“…Semiconductors are appropriate materials for understanding nonlinear dynamics phenomena because electrical currents, field, and other quantities can be performed under precisely controlled conditions [1][2][3]. The semi-insulating (SI) GaAs samples grown by low temperature (LT) molecular beam epitaxy (MBE) present a high density of As anti-site defects (around 10 19 cm −3 ).…”

Section: Introductionmentioning

confidence: 99%

Low frequency oscillations and bifurcation diagram in semi-insulating GaAs samples

Silva¹,

Albuquerque²,

Rubinger³

et al. 2006

Braz. J. Phys.

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We present an experimental study of bifurcation diagrams from low frequency current oscillations (LFO) measurements obtained from semi-insulating GaAs samples grown by low temperature molecular beam Epitaxy (LT-MBE). The considered growth temperatures were 215˚C and 265˚C. LFO are considered to be spontaneously generated oscillations under constant applied bias V . These oscillations were measurement and recorded in the form of time series. The bifurcation diagrams were obtained from the sequence of minima as a function of the applied bias. The standard measurement procedure was described elsewhere. As the control parameter, the bias allows the identification of a bifurcation route to chaos.

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Low-frequency oscillations and routes to chaos in semi-insulating GaAs

Cited by 27 publications

References 8 publications

Non-linear transport and structure formation in semi-insulating GaAs

Non-linear transport and structure formation in semi-insulating GaAs

Sequence of different types of nonlinear current oscillation in n-GaAs

Low frequency oscillations and bifurcation diagram in semi-insulating GaAs samples

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