Electron Mobility in ZnMgO/ZnO Heterostructures in the Bloch–Grüneisen Regime

Li, Qun; Zhang, Jingwen; Chong, Jing; Hou, Xun

doi:10.7567/apex.6.121102

Cited by 7 publications

(9 citation statements)

References 18 publications

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“…2(c) as a function of temperature. As in the previous study, the mobility shows a progressively upward increase down to 1 K, which is interpreted in terms of Bloch-Gruneisen regime for the acoustic phonons, 19,20 followed by saturating behavior below the temperature. The low-temperature mobility of the standard sample is comparable to that reported previously at the same x (Ref.…”

Section: Resultssupporting

confidence: 80%

Alloy disorder modulated electron transport at MgxZn1-xO/ZnO heterointerface

et al. 2017

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High-mobility electron systems in two dimensions have been the platform for realizing many fascinating quantum phenomena at low temperatures. Continuous demand to improve the sample quality has necessitated the investigations of various disorders influencing the quantum transport. Here, we study the effect of short-ranged alloy disorder on the scattering of two-dimensional electron system in MgxZn1-xO/ZnO. For this purpose, we employ a modified interface profile consisting of Mg0.01Zn0.99O/ZnO with a thin (2nm) MgxZn1-xO interlayer with x ranging from 0.005 to 0.4. This interlayer design allows us to investigate scattering mechanisms at a nearly constant carrier density as the interlayer is found not to significantly affect the carrier density but enhance alloy disorder. While the transport scattering time (τtr) shows a strong correlation with x, the quantum scattering time (τq) remains insensitive to x. The large variation in the τtr/τq ratio (from 16.2 to 1.5 corresponding to x from 0.005 to 0.4) implies a change in the dominant scattering mechanism from long range towards short range with increasing x. The insensitivity of τq on x indicates the scattering rate is not dominated by the alloy disorder. This implies that other scattering mechanisms, likely unintentional background impurities or remote surface disorders, are dominant in limiting τq, and therefore providing a prospect for pursuing ever higher levels in the quality of the two-dimensional electron system in MgxZn1-xO/ZnO system.

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Section: Resultssupporting

confidence: 80%

Alloy disorder modulated electron transport at MgxZn1-xO/ZnO heterointerface

et al. 2017

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“…While the AlGaAs/GaAs 2,6,7,23 and AlGaN/GaN [24][25][26] show enhanced scattering times with increasing density due to more effective screening of background impurities 3 and charged dislocations, 27 respectively, the scattering times in the Mg x Zn 1Àx O/ZnO 2DES are suppressed due to enhanced alloy scattering for the same range of densities. 16 In the dilute regime (n % 1 Â 10 11 cm À2 ), the data set conveys that in terms of both s tr and s q , scattering times in MgZnO/ZnO heterostructures are comparable with high quality AlGaAs/GaAs heterostructures with mobility on the order of 10 7 cm 2 /V s which show fragile fractional quantum Hall features, such as the ¼ 5/2 state. 2,6,7 Along with the AlGaAs/GaAs two-dimensional hole system (2DHS), 28,29 these three platforms stand out as the highest quality available, ahead of the AlGaAs/AlAs, 30,31 AlGaN/GaN, [24][25][26] and LaAlO 3 /SrTiO 3 , 32 although recent progress is being made for this latter system.…”

Section: Drmentioning

confidence: 75%

“…10 Rather, s tr /s q approaches % 20 when delving into more dilute samples and effects of interface roughness are mitigated. 16 This final value may be within the realms of homogeneous background impurity limited scattering times, 21,22 but we cannot rule out other potential origins such as the sample surface which is on the order of 500 nm away from the 2DES.…”

Section: Drmentioning

confidence: 91%

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Electron scattering times in ZnO based polar heterostructures

Falson

Kozuka

Smet

et al. 2015

Applied Physics Letters

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The remarkable historic advances experienced in condensed matter physics have been enabled through the continued exploration and proliferation of increasingly richer and cleaner material systems. In this work, we report on the scattering times of charge carriers confined in state-of-theart MgZnO/ZnO heterostructures displaying electron mobilities in excess of 10 6 cm 2 /V s. Through an examination of low field quantum oscillations, we obtain the effective mass of charge carriers, along with the transport and quantum scattering times. These times compare favorably with high mobility AlGaAs/GaAs heterostructures, suggesting the quality of MgZnO/ZnO heterostructures now rivals that of traditional semiconductors. V

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“…However, the calculations in the EP regime are valid only at high temperatures, when phonon energy is negligibly small compared with the thermal energy of electrons [14], and the LFC is very important for a 2DEG in MgZnO/ZnO HSs because the interaction parameter r s is much larger compared to the one in AlGaAs/GaAs heterostructures due to the larger effective mass in ZnO based materials [9][10]13]. Li and coworkers [17] have calculated the mobility of 2DEG in ZnMgO/ZnO HSs in the BG regime, when the acoustic phonon energy is comparable to the thermal energy of electrons, taking into account exchange and correlation effects. They have, however, considered only the temperature dependence using one form of the LFC, and have neglected the LO phonon contribution to the total mobility.…”

Section: Introductionmentioning

confidence: 99%

Relaxation Rate and Mobility of a Two-dimensional Electron Gas in MgZnO/ZnO Heterostructures Including Exchange and Correlation Effects

Tai

2017

Comm. in Phys.

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We investigate the relaxation rate and mobility of a two-dimensional electron gas (2DEG) confined in MgZnO/ZnO heterostructures (HSs) for temperaturesT ≤ 300K, taking into account exchange and correlation effects. We use the variational-subband-wave-function model for carrier confinement and assume that the electrons are confined to the lowest subband and scattered by acoustic phonons via deformation potential (DP) and piezoelectric (PE) fields, polar LO phonons, interface roughness (IRS), interface charges (IFCs) and the background impurities (BIs). The calculations are based on the linearized Boltzmann equation (BE) and the relaxation time approximation, assuming the scattering by acoustic phonons to be quasi-elastic. We consider three physically distinct temperature ranges with respect to phonon scattering: the Bloch-Grüneisen (BG), equipartition (EP), and inelastic regimes. In the inelastic regime at high temperatures, where the scattering from polar LO phonons becomes important, we solve directly the linearized BE by an iterative method and compare the obtained results with those of the low-temperature and high-energy relaxation-time approximation. Our calculated low-temperature mobility is in good agreement with the recent experiment.

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Electron Mobility in ZnMgO/ZnO Heterostructures in the Bloch–Grüneisen Regime

Cited by 7 publications

References 18 publications

Alloy disorder modulated electron transport at MgxZn1-xO/ZnO heterointerface

Alloy disorder modulated electron transport at MgxZn1-xO/ZnO heterointerface

Electron scattering times in ZnO based polar heterostructures

Relaxation Rate and Mobility of a Two-dimensional Electron Gas in MgZnO/ZnO Heterostructures Including Exchange and Correlation Effects

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