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Semiconductor Nanoelectronic Devices Based on Ballistic and Quantum Effects

Sun, Jie LU (2009)
Abstract
As current silicon-based microelectronic devices and circuits are approaching

their fundamental limits, the research field of nanoelectronics is emerging

worldwide. With this background, the present thesis focuses on semiconductor

nanoelectronic devices based on ballistic and quantum effects.

<br>

The main material studied was a modulation doped In0.75Ga0.25As/InP semiconductor two-dimensional electron gas grown by metal-organic vapor phase epitaxy.

The thesis covers mainly three types of devices and their twofold integration:

in-plane gate transistors, three-terminal ballistic junctions and quantum

dots. Various advanced nanofabrication tools were used to... (More)
As current silicon-based microelectronic devices and circuits are approaching

their fundamental limits, the research field of nanoelectronics is emerging

worldwide. With this background, the present thesis focuses on semiconductor

nanoelectronic devices based on ballistic and quantum effects.

<br>

The main material studied was a modulation doped In0.75Ga0.25As/InP semiconductor two-dimensional electron gas grown by metal-organic vapor phase epitaxy.

The thesis covers mainly three types of devices and their twofold integration:

in-plane gate transistors, three-terminal ballistic junctions and quantum

dots. Various advanced nanofabrication tools were used to realize the devices, such as electron beam lithography, focused ion beam lithography and atomic layer deposition. The theories behind the analysis of the experimental data include principles of field effect transistors, the Landauer-Büttiker formalism, the constant interaction model, etc.

The principles of in-plane gate transistors can be explained by a classical

theory. The source, drain, one-dimensional channel and two side gates were

in the same plane; a setup that can be obtained by single step lithography.

The gating efficiency of the two independent gates was voltage-dependent,

which resulted in a simplified circuitry for implementing a logic function. At

room temperature, an SR latch with a signal gain of ∼4 was realized by the

integration of two in-plane gate transistors.

Three-terminal ballistic junctions are nonlinear devices based on ballistic

electron transport. When two terminals are applied with voltages, the third

terminal will output a voltage close to the more negative voltage in the two

inputs, as opposed to a simple average of the two. From numerical calculations,

this ballistic effect persists up to room temperature. Three-terminal

ballistic junctions are so robust that nonlinearity is observable in asymmetric

devices and relatively large devices. They can be fabricated on several

materials by assorted techniques. The junctions find their applications in

analogue frequency mixers, phase detectors and digital SR latches and the

circuits are simpler than conventional designs. The intrinsic speed of the

devices is in the GHz or THz regime by virtue of the ballistic transport. It is believed that as-built junctions have a potential as building blocks in future

nanoelectronics.

Quantum dots are zero-dimensional boxes for electrons with a decent

resemblance to natural atoms. Due to their nanoscale size, numerous interesting

quantum effects can be observed. Gate-defined quantum dots were

fabricated in InGaAs/InP by incorporating a high-k HfO2 (20-30 nm thick,

grown by atomic layer deposition) as the gate dielectric. The gate leakage

was suppressed and the gating efficiency improved. At 300 mK, charge stability

diagrams of single and double quantum dots were measured and studied

in detail. Zeeman splitting in a parallel magnetic field and charge sensing by

nearby quantum point contacts were also investigated. The single and double

quantum dots are expected to be useful in fields including single electron

logic, stochastic resonance, spintronics, quantum computing, etc. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof. Bird, Jonathan, Electrical Engineering Department, University at Buffalo, NY, USA
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Semiconductor, Quantum Dots, Ballistic Transport, InGaAs/InP 2DEG, Nanoelectronics
pages
125 pages
publisher
Lund University (Media-Tryck)
defense location
Lecture hall B, Fysiska Institutionen, Professorsgatan 1, Lund University Faculty of Engineering
defense date
2009-09-25 13:15
ISBN
978-91-628-7850-4
language
English
LU publication?
yes
id
c48d7aff-2236-4ddf-a3ea-c751cc4ba5ad (old id 1467890)
date added to LUP
2009-08-31 13:10:25
date last changed
2016-09-19 08:45:08
@misc{c48d7aff-2236-4ddf-a3ea-c751cc4ba5ad,
  abstract     = {As current silicon-based microelectronic devices and circuits are approaching<br/><br>
their fundamental limits, the research field of nanoelectronics is emerging<br/><br>
worldwide. With this background, the present thesis focuses on semiconductor<br/><br>
nanoelectronic devices based on ballistic and quantum effects.<br/><br>
&lt;br&gt; <br/><br>
The main material studied was a modulation doped In0.75Ga0.25As/InP semiconductor two-dimensional electron gas grown by metal-organic vapor phase epitaxy.<br/><br>
The thesis covers mainly three types of devices and their twofold integration:<br/><br>
in-plane gate transistors, three-terminal ballistic junctions and quantum<br/><br>
dots. Various advanced nanofabrication tools were used to realize the devices, such as electron beam lithography, focused ion beam lithography and atomic layer deposition. The theories behind the analysis of the experimental data include principles of field effect transistors, the Landauer-Büttiker formalism, the constant interaction model, etc.<br/><br>
The principles of in-plane gate transistors can be explained by a classical<br/><br>
theory. The source, drain, one-dimensional channel and two side gates were<br/><br>
in the same plane; a setup that can be obtained by single step lithography.<br/><br>
The gating efficiency of the two independent gates was voltage-dependent,<br/><br>
which resulted in a simplified circuitry for implementing a logic function. At<br/><br>
room temperature, an SR latch with a signal gain of ∼4 was realized by the<br/><br>
integration of two in-plane gate transistors.<br/><br>
Three-terminal ballistic junctions are nonlinear devices based on ballistic<br/><br>
electron transport. When two terminals are applied with voltages, the third<br/><br>
terminal will output a voltage close to the more negative voltage in the two<br/><br>
inputs, as opposed to a simple average of the two. From numerical calculations,<br/><br>
this ballistic effect persists up to room temperature. Three-terminal<br/><br>
ballistic junctions are so robust that nonlinearity is observable in asymmetric<br/><br>
devices and relatively large devices. They can be fabricated on several<br/><br>
materials by assorted techniques. The junctions find their applications in<br/><br>
analogue frequency mixers, phase detectors and digital SR latches and the<br/><br>
circuits are simpler than conventional designs. The intrinsic speed of the<br/><br>
devices is in the GHz or THz regime by virtue of the ballistic transport. It is believed that as-built junctions have a potential as building blocks in future<br/><br>
nanoelectronics.<br/><br>
Quantum dots are zero-dimensional boxes for electrons with a decent<br/><br>
resemblance to natural atoms. Due to their nanoscale size, numerous interesting<br/><br>
quantum effects can be observed. Gate-defined quantum dots were<br/><br>
fabricated in InGaAs/InP by incorporating a high-k HfO2 (20-30 nm thick,<br/><br>
grown by atomic layer deposition) as the gate dielectric. The gate leakage<br/><br>
was suppressed and the gating efficiency improved. At 300 mK, charge stability<br/><br>
diagrams of single and double quantum dots were measured and studied<br/><br>
in detail. Zeeman splitting in a parallel magnetic field and charge sensing by<br/><br>
nearby quantum point contacts were also investigated. The single and double<br/><br>
quantum dots are expected to be useful in fields including single electron<br/><br>
logic, stochastic resonance, spintronics, quantum computing, etc.},
  author       = {Sun, Jie},
  isbn         = {978-91-628-7850-4},
  keyword      = {Semiconductor,Quantum Dots,Ballistic Transport,InGaAs/InP 2DEG,Nanoelectronics},
  language     = {eng},
  pages        = {125},
  publisher    = {ARRAY(0x887cce0)},
  title        = {Semiconductor Nanoelectronic Devices Based on Ballistic and Quantum Effects},
  year         = {2009},
}