Self-oscillations in weakly coupled GaAs/AlGaAs superlattices at 77.3 K

Rasulova, G. K.; Brunkov, P. N.; Egorov, A. Yu.; Zhukov, A. E.

doi:10.1063/1.3072697

Cited by 8 publications

(4 citation statements)

References 21 publications

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“…The technique we have presented is not limited to QCLs, but is applicable to many other active quantum devices and nanoelectronics, such as quantum-well infrared photodetectors (QWIP), semiconductor quantum-well optical amplifiers, semiconductor modulators, single electron transistors, spintronic devices, oscillators based on resonant tunneling and Gunn effect, to name but a few. The domain boundary in our measured QCLs looks stable with a sharp transition from one domain to another but the SVM technique could be able to probe domain instability in weakly-coupled semiconductor superlattices 54 at nanometer scales, which so far have been attracting extensive research interests 55 56 57 58 59 .…”

mentioning

confidence: 96%

Direct Nanoscale Imaging of Evolving Electric Field Domains in Quantum Structures

Dhar

Razavipour

Dupont

et al. 2014

Sci Rep

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The external performance of quantum optoelectronic devices is governed by the spatial profiles of electrons and potentials within the active regions of these devices. For example, in quantum cascade lasers (QCLs), the electric field domain (EFD) hypothesis posits that the potential distribution might be simultaneously spatially nonuniform and temporally unstable. Unfortunately, there exists no prior means of probing the inner potential profile directly. Here we report the nanoscale measured electric potential distribution inside operating QCLs by using scanning voltage microscopy at a cryogenic temperature. We prove that, per the EFD hypothesis, the multi-quantum-well active region is indeed divided into multiple sections having distinctly different electric fields. The electric field across these serially-stacked quantum cascade modules does not continuously increase in proportion to gradual increases in the applied device bias, but rather hops between discrete values that are related to tunneling resonances. We also report the evolution of EFDs, finding that an incremental change in device bias leads to a hopping-style shift in the EFD boundary – the higher electric field domain expands at least one module each step at the expense of the lower field domain within the active region.

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mentioning

confidence: 96%

Direct Nanoscale Imaging of Evolving Electric Field Domains in Quantum Structures

Dhar

Razavipour

Dupont

et al. 2014

Sci Rep

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“…[15][16][17] In 1987, Tsuchiya et al 18 measured the time taken when electron passes the AlAs-GaAs-AlAs double-barrier structure and got the experimental result of tunneling lifetime for the first time. [15][16][17] In 1987, Tsuchiya et al 18 measured the time taken when electron passes the AlAs-GaAs-AlAs double-barrier structure and got the experimental result of tunneling lifetime for the first time.…”

Section: Barrier Dependent Electron Tunneling Lifetime In One-dimensimentioning

confidence: 99%

Barrier dependent electron tunneling lifetime in one-dimensional device structures

Gong

et al. 2010

Journal of Applied Physics

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The tunneling times of electrons in one-dimensional potential structures were studied using a projected Green function ͑PGF͒ method. The approach was applied to cases with potentials with one barrier, two barriers, and three barriers at the right side of a quantum well where the electron is located at the initial time. Our results include the effects of well width and barrier thickness on the tunneling time, and also show the impact on the tunneling time of splitting a single barrier into more barriers. This study confirms not only the validity of the PGF method but also reveals the impact of the potential structure on the operation speed of resonant tunneling devices.

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“…[2][3][4][5][6][7][8][9][10] Electrons in semiconductor SLs exhibit a wide range of nonlinear effects under external fields. [11][12][13][14] These are of fundamental scientific interest and useful for applications in ultrafast electronics. Presently the following directions stand out: SLs with lower dimensions, [15] generation of THz signals, [16] self-sustained current oscillations (SSCOs), and nonlinear dynamics.…”

Section: Introductionmentioning

confidence: 99%

Dependence of electron dynamics on magnetic fields in semiconductor superlattices

2013

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Numerical simulation results are presented for a drift-diffusion rate equation model which describes electronic transport due to sequential tunneling between adjacent quantum wells in weakly coupled semiconductor superlattices (SLs). The electron dynamics is dependent on the external magnetic field perpendicular to the electron motion direction, and a detailed explanation is given. Using different parameters, the system shows different dynamic behaviors, and three distinct phenomena are observed and controlled by increasing magnetic field. (i) For a lower doping density, the system state transfers from stable state to oscillationary state. (ii) An opposite result is obtained to that in the case (i) for an intermediate value of the doping density, and the state changes from oscillationary to stationary. (iii) The state varies between oscillationary and stationary when doping density is large. Then, a detailed theoretical analysis is given to explain these surprise phenomena. The distribution of the electric-field domain along the SLs is plotted. We find the structure of the domain is almost uniform for a lower doping density, and no domain occurs in the SLs. By adding an external ac signal, complex nonlinear behaviors are observed from the Poincaré map and the corresponding phase diagrams when the driving frequency changes.

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Self-oscillations in weakly coupled GaAs/AlGaAs superlattices at 77.3 K

Cited by 8 publications

References 21 publications

Direct Nanoscale Imaging of Evolving Electric Field Domains in Quantum Structures

Direct Nanoscale Imaging of Evolving Electric Field Domains in Quantum Structures

Barrier dependent electron tunneling lifetime in one-dimensional device structures

Dependence of electron dynamics on magnetic fields in semiconductor superlattices

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