PhD researcher on Modeling two-dimensional topological insulator field-effect transistors

Leuven - PhD
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To maintain electrostatic control in nanoscale electronic devices, the use of two-dimensional (2D) materials will become inevitable. Many two-dimensional materials have been put forward for transistor applications, such as graphene, transition-metal dichalcogenides, phosphorene, … At the same time, new device concepts such as tunnel field-effect transistors (TFETs), ferroelectric-based FETs, Bose-Einstein condensation-based devices, spin-based devices. Unfortunately, up to now, no competitive materials or device system has emerged. A major problem for many of the new devices is the material quality which has too many “imperfections”. Almost all of the 2D materials invariably have a very large number of defects hampering device performance. At interfaces there are a large number of electronic interface states and surfaces or edges are often rough rather than smooth. All of these imperfections severely degrade device performance in any new two-dimensional device.

In this project, the student will study 2D topological insulators (TIs) for field-effect transistor (FET) applications. The key feature of 2D TIs, compared to other 2D materials, is their topologically protected edge states. These edge states are spin-polarized and backscattering in the edge states is almost completely suppressed. This leads to excellent device performance, even in the presence of a significant number of imperfections. Initial estimates by prof. Vandenberghe indicate that TI FETs are competitive with future high-performance devices while being more energy-efficient than low-power alternatives. The demonstration of a high-performance low-power device based on 2D materials, that can be fabricated with imperfections, would be truly revolutionary.

This topic is suited for students interested in studying electron transport at the nanoscale using theoretical methods. The research will consist of using existing codes to study materials, developing new theoretical approaches, and writing the appropriate code to study electronic properties of 2D TIs and TI FETs. The student can use the results of first principles calculations, in-house codes at the University of Texas at Dallas (UT Dallas) and imec/KU Leuven, and the student will further develop the required physical framework and code to model TI FETs.

The research will be conducted jointly between imec/KU Leuven, Belgium and the department of materials Science at UT Dallas. Both are world-renowned institutions in the field of nanoelectronics research. Upon completion of the PhD program, the student will be awarded a PhD degree from KU Leuven and UT Dallas. In the first stages of the PhD, research will mainly take place at UT Dallas where the student will take up coursework (tuition will be paid by UT Dallas).

Required background: 

Electronic device physics, Quantum Mechanics, Computational Nano-electronics.

Type of work:

The research will consist of using existing codes to study materials, developing new theoretical approaches, and writing the appropriate code to study electronic properties in new materials and devices.

Supervisor: Bart Soree (imec/KU Leuven) and William Vandenberghe (UT Dallas)

Daily advisor: Bart Soree (imec/KU Leuven) and William Vandenberghe (UT Dallas)

When you apply for this PhD project, mention the following reference code in the imec application form: ref. STS 1704-04.

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