Electron Scattering Mechanisms in Low-Dimensional Transport Physics

Qin Wang

Electron Scattering Mechanisms in Low-Dimensional Transport Physics

Qin Wang

Research output: Thesis › Doctoral Thesis (compilation)

Abstract

Electron scattering mechanisms in low-dimensional semiconductor systems have been investigated at low temperatures.

The influence of scatterers on magnetotransport in a high-mobility, GaAs/AlGaAs two-dimensional electron gas (2DEG) system was studied. A certain number of scattering centres are introduced into the 2DEGs by proton irradiation and can be removed by annealing. The transport properties were compared before and after irradiation and subsequent annealing.

The Coulomb scattering and alloy scattering in modulation-doped GaInAs/InP quantum wells (QWs) have been studied. To modify the Coulomb scattering, the self-assembled InAs quantum dots located just above the QWs were produced by MOVPE. A top gate was used to control the charging and decharging of the InAs dots. The experimental results show that the Coulomb field from the trapped electrons is important for inter-channel scattering processes between edge channels formed in magnetic fields. Also, the fractional quantum Hall effect (FQHE) is observed in the GaInAs/InP QWs. To the best of our knowledge, this is the first observation of the FQHE in GaInAs/InP quantum wells.

The fabrication and characterization of regrown GaInAs/InP electron waveguides are presented. In particular, the conductance oscillations induced by the formation of longitudinal resonant electron states in the waveguide are observed and analysed.

Original language	English
Qualification	Doctor
Awarding Institution	Solid State Physics
Supervisors/Advisors	[unknown], [unknown], Supervisor, External person
Award date	1999 May 4
Publisher	Solid State Physics, Lund University
ISBN (Print)	91-628-3436-3
Publication status	Published - 1999
Externally published	Yes

Bibliographical note

Defence details

Date: 1999-05-04
Time: 10:15
Place: Fysiska institutionens föreläsningssal A

External reviewer(s)

Name: Lindelof, Poul Erik
Title: Prof
Affiliation: Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark

---

I. Transport Properties of Proton-Irradiated AlGaAs/GaAs Two-Dimensional Electron Gas StructuresQin Wang, Hongqi Xu, P. Omling, C. Yang and K.G. MalmqvistSubmitted to Nucl. Instr. and Meth. in Phys. Res. B
 
II. Defect-Induced Overshoot of Quantum Hall PlateausQin Wang, Hongqi Xu, P. Omling, C. Yang and K.G. MalmqvistSubmitted to J. Appl. Phys.
 
III. Ga0.25In0.75As/InP Quantum Wells with Extremely High and Anisotropic Two-Dimensional Electron Gas MobilitiesP. Ramvall, N. Carlsson, P. Omling, L. Samuelson, W. Seifert, M. Stolze and Q.WangAppl. Phys. Lett. 68 (1996) 1111
 
IV. Tuning of the Single-Particle Relaxation Time of a High-Mobility Electron Gas in aGa0.25In0.75As/InP Quantum WellP. Ramvall, N. Carlsson, P. Omling, L. Samuelson, W. Seifert and Q. WangAppl. Phys. Lett. 70 (1997) 243
 
V. Effects of Charged Self-Assembled Quantum Dots on Two-Dimensional Quantum TransportQin Wang, N. Carlsson, P. Omling, L. Samuelson and W. SeifertTo be submitted to Appl. Phys. Lett.
 
VI. Observation of Fractional Quantum Hall Effect in Ga0.25In0.75As/InP Quantum WellsQin Wang, N. Carlsson, P. Omling, L. Samuelson and W. SeifertManuscript
 
VII. Quantized Conductance in a Heterostructurally Defined Ga0.25In0.75As/InP QuantumWireP. Ramvall, N. Carlsson, I. Maximov, P. Omling, L. Samuelson, W. Seifert, Q.Wang and S. LourdudossAppl. Phys. Lett. 71 (1997) 918
 
VIII. Conductance Oscillations Induced by Longitudinal Resonant States in Hetero- epitaxially Defined Ga0.25In0.75As/InP Electron WaveguidesQin Wang, N. Carlsson, I. Maximov, P. Omling, L. Samuelson, W. Seifert,Weidong Sheng, I. Shorubalko and Hongqi XuSubmitted to Appl. Phys. Lett.

Subject classification (UKÄ)

Condensed Matter Physics

Free keywords

electron scattering mechanisms
mobility
scattering time
Coulomb scattering
alloy scattering
edge states
quantum Hall effect
SdH
conductance oscillations
quantized conductance
GaInAs/InP
Low-dimensional structures
GaAs/AlGaAs
Physics
Fysik
Fysicumarkivet A:1999:Wang

Cite this

@phdthesis{06cbda7d009740c08af94774e903d338,

title = "Electron Scattering Mechanisms in Low-Dimensional Transport Physics",

abstract = "Electron scattering mechanisms in low-dimensional semiconductor systems have been investigated at low temperatures. The influence of scatterers on magnetotransport in a high-mobility, GaAs/AlGaAs two-dimensional electron gas (2DEG) system was studied. A certain number of scattering centres are introduced into the 2DEGs by proton irradiation and can be removed by annealing. The transport properties were compared before and after irradiation and subsequent annealing. The Coulomb scattering and alloy scattering in modulation-doped GaInAs/InP quantum wells (QWs) have been studied. To modify the Coulomb scattering, the self-assembled InAs quantum dots located just above the QWs were produced by MOVPE. A top gate was used to control the charging and decharging of the InAs dots. The experimental results show that the Coulomb field from the trapped electrons is important for inter-channel scattering processes between edge channels formed in magnetic fields. Also, the fractional quantum Hall effect (FQHE) is observed in the GaInAs/InP QWs. To the best of our knowledge, this is the first observation of the FQHE in GaInAs/InP quantum wells. The fabrication and characterization of regrown GaInAs/InP electron waveguides are presented. In particular, the conductance oscillations induced by the formation of longitudinal resonant electron states in the waveguide are observed and analysed.",

keywords = "electron scattering mechanisms, mobility, scattering time, Coulomb scattering, alloy scattering, edge states, quantum Hall effect, SdH, conductance oscillations, quantized conductance, GaInAs/InP, Low-dimensional structures, GaAs/AlGaAs, Physics, Fysik, Fysicumarkivet A:1999:Wang",

author = "Qin Wang",

note = "Defence details Date: 1999-05-04 Time: 10:15 Place: Fysiska institutionens f{\"o}rel{\"a}sningssal A External reviewer(s) Name: Lindelof, Poul Erik Title: Prof Affiliation: Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark --- I. Transport Properties of Proton-Irradiated AlGaAs/GaAs Two-Dimensional Electron Gas StructuresQin Wang, Hongqi Xu, P. Omling, C. Yang and K.G. MalmqvistSubmitted to Nucl. Instr. and Meth. in Phys. Res. B II. Defect-Induced Overshoot of Quantum Hall PlateausQin Wang, Hongqi Xu, P. Omling, C. Yang and K.G. MalmqvistSubmitted to J. Appl. Phys. III. Ga0.25In0.75As/InP Quantum Wells with Extremely High and Anisotropic Two-Dimensional Electron Gas MobilitiesP. Ramvall, N. Carlsson, P. Omling, L. Samuelson, W. Seifert, M. Stolze and Q.WangAppl. Phys. Lett. 68 (1996) 1111 IV. Tuning of the Single-Particle Relaxation Time of a High-Mobility Electron Gas in aGa0.25In0.75As/InP Quantum WellP. Ramvall, N. Carlsson, P. Omling, L. Samuelson, W. Seifert and Q. WangAppl. Phys. Lett. 70 (1997) 243 V. Effects of Charged Self-Assembled Quantum Dots on Two-Dimensional Quantum TransportQin Wang, N. Carlsson, P. Omling, L. Samuelson and W. SeifertTo be submitted to Appl. Phys. Lett. VI. Observation of Fractional Quantum Hall Effect in Ga0.25In0.75As/InP Quantum WellsQin Wang, N. Carlsson, P. Omling, L. Samuelson and W. SeifertManuscript VII. Quantized Conductance in a Heterostructurally Defined Ga0.25In0.75As/InP QuantumWireP. Ramvall, N. Carlsson, I. Maximov, P. Omling, L. Samuelson, W. Seifert, Q.Wang and S. LourdudossAppl. Phys. Lett. 71 (1997) 918 VIII. Conductance Oscillations Induced by Longitudinal Resonant States in Hetero- epitaxially Defined Ga0.25In0.75As/InP Electron WaveguidesQin Wang, N. Carlsson, I. Maximov, P. Omling, L. Samuelson, W. Seifert,Weidong Sheng, I. Shorubalko and Hongqi XuSubmitted to Appl. Phys. Lett.",

year = "1999",

language = "English",

isbn = "91-628-3436-3",

publisher = "Solid State Physics, Lund University",

type = "Doctoral Thesis (compilation)",

school = "Solid State Physics",

}

TY - THES

T1 - Electron Scattering Mechanisms in Low-Dimensional Transport Physics

AU - Wang, Qin

N1 - Defence details Date: 1999-05-04 Time: 10:15 Place: Fysiska institutionens föreläsningssal A External reviewer(s) Name: Lindelof, Poul Erik Title: Prof Affiliation: Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark --- I. Transport Properties of Proton-Irradiated AlGaAs/GaAs Two-Dimensional Electron Gas StructuresQin Wang, Hongqi Xu, P. Omling, C. Yang and K.G. MalmqvistSubmitted to Nucl. Instr. and Meth. in Phys. Res. B II. Defect-Induced Overshoot of Quantum Hall PlateausQin Wang, Hongqi Xu, P. Omling, C. Yang and K.G. MalmqvistSubmitted to J. Appl. Phys. III. Ga0.25In0.75As/InP Quantum Wells with Extremely High and Anisotropic Two-Dimensional Electron Gas MobilitiesP. Ramvall, N. Carlsson, P. Omling, L. Samuelson, W. Seifert, M. Stolze and Q.WangAppl. Phys. Lett. 68 (1996) 1111 IV. Tuning of the Single-Particle Relaxation Time of a High-Mobility Electron Gas in aGa0.25In0.75As/InP Quantum WellP. Ramvall, N. Carlsson, P. Omling, L. Samuelson, W. Seifert and Q. WangAppl. Phys. Lett. 70 (1997) 243 V. Effects of Charged Self-Assembled Quantum Dots on Two-Dimensional Quantum TransportQin Wang, N. Carlsson, P. Omling, L. Samuelson and W. SeifertTo be submitted to Appl. Phys. Lett. VI. Observation of Fractional Quantum Hall Effect in Ga0.25In0.75As/InP Quantum WellsQin Wang, N. Carlsson, P. Omling, L. Samuelson and W. SeifertManuscript VII. Quantized Conductance in a Heterostructurally Defined Ga0.25In0.75As/InP QuantumWireP. Ramvall, N. Carlsson, I. Maximov, P. Omling, L. Samuelson, W. Seifert, Q.Wang and S. LourdudossAppl. Phys. Lett. 71 (1997) 918 VIII. Conductance Oscillations Induced by Longitudinal Resonant States in Hetero- epitaxially Defined Ga0.25In0.75As/InP Electron WaveguidesQin Wang, N. Carlsson, I. Maximov, P. Omling, L. Samuelson, W. Seifert,Weidong Sheng, I. Shorubalko and Hongqi XuSubmitted to Appl. Phys. Lett.

PY - 1999

Y1 - 1999

N2 - Electron scattering mechanisms in low-dimensional semiconductor systems have been investigated at low temperatures. The influence of scatterers on magnetotransport in a high-mobility, GaAs/AlGaAs two-dimensional electron gas (2DEG) system was studied. A certain number of scattering centres are introduced into the 2DEGs by proton irradiation and can be removed by annealing. The transport properties were compared before and after irradiation and subsequent annealing. The Coulomb scattering and alloy scattering in modulation-doped GaInAs/InP quantum wells (QWs) have been studied. To modify the Coulomb scattering, the self-assembled InAs quantum dots located just above the QWs were produced by MOVPE. A top gate was used to control the charging and decharging of the InAs dots. The experimental results show that the Coulomb field from the trapped electrons is important for inter-channel scattering processes between edge channels formed in magnetic fields. Also, the fractional quantum Hall effect (FQHE) is observed in the GaInAs/InP QWs. To the best of our knowledge, this is the first observation of the FQHE in GaInAs/InP quantum wells. The fabrication and characterization of regrown GaInAs/InP electron waveguides are presented. In particular, the conductance oscillations induced by the formation of longitudinal resonant electron states in the waveguide are observed and analysed.

AB - Electron scattering mechanisms in low-dimensional semiconductor systems have been investigated at low temperatures. The influence of scatterers on magnetotransport in a high-mobility, GaAs/AlGaAs two-dimensional electron gas (2DEG) system was studied. A certain number of scattering centres are introduced into the 2DEGs by proton irradiation and can be removed by annealing. The transport properties were compared before and after irradiation and subsequent annealing. The Coulomb scattering and alloy scattering in modulation-doped GaInAs/InP quantum wells (QWs) have been studied. To modify the Coulomb scattering, the self-assembled InAs quantum dots located just above the QWs were produced by MOVPE. A top gate was used to control the charging and decharging of the InAs dots. The experimental results show that the Coulomb field from the trapped electrons is important for inter-channel scattering processes between edge channels formed in magnetic fields. Also, the fractional quantum Hall effect (FQHE) is observed in the GaInAs/InP QWs. To the best of our knowledge, this is the first observation of the FQHE in GaInAs/InP quantum wells. The fabrication and characterization of regrown GaInAs/InP electron waveguides are presented. In particular, the conductance oscillations induced by the formation of longitudinal resonant electron states in the waveguide are observed and analysed.

KW - electron scattering mechanisms

KW - mobility

KW - scattering time

KW - Coulomb scattering

KW - alloy scattering

KW - edge states

KW - quantum Hall effect

KW - SdH

KW - conductance oscillations

KW - quantized conductance

KW - GaInAs/InP

KW - Low-dimensional structures

KW - GaAs/AlGaAs

KW - Physics

KW - Fysik

KW - Fysicumarkivet A:1999:Wang

M3 - Doctoral Thesis (compilation)

SN - 91-628-3436-3

PB - Solid State Physics, Lund University

ER -

Electron Scattering Mechanisms in Low-Dimensional Transport Physics

Abstract

Bibliographical note

Subject classification (UKÄ)

Free keywords

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Cite this