Low field mobility of 2-d electron gas in modulation doped AlxGa1−xAs/GaAs layers

Lee, K.; Shur, M. S.; Drummond, T. J.; Morkoç̌, H.

doi:10.1063/1.331922

Cited by 174 publications

(51 citation statements)

References 24 publications

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“…This neglect of charge due to surface compensation is typical in these types of calculations. 17,26,27 For our purposes, though, the exact value of N RI is not important since it will not change the qualitative dependence of the RI-limited mobility as p is varied.…”

Section: 11mentioning

confidence: 99%

Exploration of the limits to mobility in two-dimensional hole systems in GaAs/AlGaAs quantum wells

et al. 2012

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We report on the growth and electrical characterization of a series of two-dimensional hole systems (2DHSs) used to study the density dependence of low temperature mobility in 20 nm GaAs/AlGaAs quantum wells. The hole density was controlled by changing the Al mole fraction and the setback of the delta-doping layer. We varied the density over a range from 1.8 × 10 10 cm −2 to 1.9 × 10 11 cm −2 finding a nonmonotonic dependence of mobility on density at T = 0.3 K. Surprisingly, a peak mobility of 2.3 × 10 6 cm 2 /Vs was measured at a density of 6.5 × 10 10 cm −2 with further increase in density resulting in reduced mobility. We discuss possible mechanisms leading to the observed non-monotonic density dependence of the mobility. Relying solely on interface roughness scattering to explain the observed drop in mobility at high density requires roughness parameters which are not consistent with measurements of similar electron structures. This leaves open the possibility of contributions from other scattering mechanisms at high density.Two-dimensional hole systems (2DHSs) on (001) oriented GaAs offer an interesting alternative to the more widely studied two-dimensional electron systems (2DESs). 2DHSs on (001) GaAs have effective masses roughly 4.5 to 7.5 times larger 1-3 than that in corresponding 2DESs which increases the importance of Coulomb interactions relative to the kinetic energy resulting in enhancement of importance of many-body effects. In addition, the p-wave symmetry of the valence band in GaAs leads to a much reduced hyperfine coupling of hole spins to the atomic nuclei which makes them an exciting alternative to electrons for quantum dot spinbased qubits [4][5][6] . The presence of spin-orbit coupling and light/heavy hole mixing in the valence band of GaAs also allows extensive band structure engineering 7-9 . This feature has been exploited to alter the nature of groundstates in the quantum Hall regime.

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Section: 11mentioning

confidence: 99%

Exploration of the limits to mobility in two-dimensional hole systems in GaAs/AlGaAs quantum wells

et al. 2012

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“…In equation (13), k F is the wavevector on the Fermi surface, and S 0 is the screening constant which is given for the degenerate case by Lee et al as [28] …”

Section: Background Impurity Scatteringmentioning

confidence: 99%

Scattering analysis of 2DEG carrier extracted by QMSA in undoped Al_0.25Ga_0.75N/GaN heterostructures

Li̇şesi̇vdi̇n¹,

Acar²,

Kasap³

et al. 2007

Semicond. Sci. Technol.

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Hall effect measurements on undoped Al 0.25 Ga 0.75 N/GaN heterostructures grown by a metalorganic chemical vapour deposition (MOCVD) technique have been carried out as a function of temperature (20-350 K) and magnetic field (0-1.5 T). Magnetic field dependent Hall data were analysed using the quantitative mobility spectrum analysis (QMSA) technique. The mobility and density within the two-dimensional electron gas (2DEG) at the Al 0.25 Ga 0.75 N/GaN interface and within the underlying GaN layer were successfully separated by QMSA. Mobility analysis has been carried out using both the measured Hall data at a single field and the extracted data from QMSA. Analysis of the temperature-dependent mobility of 2DEG extracted from QMSA indicates that the interface roughness and alloy disorder scattering mechanisms are the dominant scattering mechanisms at low temperatures while at high temperatures only polar optical phonon scattering is the dominant mechanism. Al 0.25 Ga 0.75 N/GaN interface related parameters such as well width, deformation potential constant and correlation length were also accurately obtained from the fits of the simple analytical expressions of scattering mechanisms to the 2DEG mobility.

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“…To estimate N ph , we note that an electron during its cooling process can emit acoustic phonon of energy q ph ranging from zero up to q ph max =2v l ͑2m e E e ͒ 1/2 −2m e v l 2 as calculated considering an elementary act of the electron-phonon interaction ͑assuming a parabolic conduction band͒, where v l = 5.2ϫ 10 5 cm/ s is the velocity of longitudinal-acoustic phonons in GaAs. 44 Thus, q ph max = 1.2 meV for E e = 19.2 meV. Assuming averaged ប ph Ϸ ប ph max / 2, we conclude N ph Ϸ 30 and, hence, ac Ϸ 3 ps, which is of the same order as of ͑5 T͒.…”

Section: Resultsmentioning

confidence: 69%

Effective tuning of the charge state of a single InAs/GaAs quantum dot by an external magnetic field

Moskalenko

Larsson

et al. 2008

Phys. Rev. B

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A microphotoluminescence study of single InAs/GaAs quantum dots ͑QDs͒ in the presence of an applied external magnetic field is presented. Attention is focused on the redistribution between the spectral lines of a single QD observed at increasing magnetic field parallel to the growth direction ͑Faraday geometry͒. The redistribution effect is explained by considering the electron drift velocity in the QD plane that affects the probability for capture into the QD. In contrast, no redistribution is observed when applying the magnetic field perpendicular to the growth direction ͑Voigt geometry͒.

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Low field mobility of 2-d electron gas in modulation doped AlxGa1−xAs/GaAs layers

Cited by 174 publications

References 24 publications

Exploration of the limits to mobility in two-dimensional hole systems in GaAs/AlGaAs quantum wells

Exploration of the limits to mobility in two-dimensional hole systems in GaAs/AlGaAs quantum wells

Scattering analysis of 2DEG carrier extracted by QMSA in undoped Al_0.25Ga_0.75N/GaN heterostructures

Effective tuning of the charge state of a single InAs/GaAs quantum dot by an external magnetic field

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Low field mobility of 2-d electron gas in modulation doped AlxGa1−xAs/GaAs layers

Cited by 174 publications

References 24 publications

Exploration of the limits to mobility in two-dimensional hole systems in GaAs/AlGaAs quantum wells

Exploration of the limits to mobility in two-dimensional hole systems in GaAs/AlGaAs quantum wells

Scattering analysis of 2DEG carrier extracted by QMSA in undoped Al0.25Ga0.75N/GaN heterostructures

Effective tuning of the charge state of a single InAs/GaAs quantum dot by an external magnetic field

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Scattering analysis of 2DEG carrier extracted by QMSA in undoped Al_0.25Ga_0.75N/GaN heterostructures