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Epitaxial growth of 2D heterostructures on SiC for electronics and gas sensing

Study level

PhD

Master of Philosophy

Honours

Vacation research experience scheme

Faculty/Lead unit

Topic status

In progress.

Supervisors

Associate Professor Jennifer MacLeod
Position
Associate Professor
Division / Faculty
Science and Engineering Faculty
Professor Nunzio Motta
Position
Professor
Division / Faculty
Science and Engineering Faculty

Overview

Graphene has attracted a great deal of interest due to its remarkable electronic, optical and mechanical properties, however the absence of a bandgap limits its use in many applications. Future applications in nanoelectronics and gas sensing will depend critically on the development of novel approaches to introduce a bandgap while preserving carrier mobility, for example by creating heterostructures of graphene with other two dimensional (2D) materials with complementary properties.

This project will explore the heteroepitaxial growth of new 2D materials to overcome the fundamental limitations of graphene, by systematically refining the integration of different heterostructures with graphene grown epitaxially on 6H- and 4H-SiC (0001). In-plane heterostructures of graphene and hexagonal boron nitride (h-BN), as well as van der Waals epitaxy of transition metal dichalcogenides (TMDs) (namely MoS2 and WS2) and MXenes will be investigated by using Scanning Tunneling Microscopy and Spectroscopy and other surface sensitive techniques.

Research activities

Activities

  • Growth of topologically defined h-BN-graphene lateral heterostructures by the chemical conversion of epitaxial graphene/SiC from boric acid and ammonia vapours.
  • Systematic study the CVD growth parameters of TMDs (namely MoS2 and WS2) tand MXenes o obtain large area monolayer films on epitaxial graphene/SiC substrates.
  • Understand the kinetics and the thermodynamics of the growth processes that lead to high-quality, large area heterostructures of graphene/SiC.
  • Demonstrate the device capabilities of graphene heterostructures grown directly on SiC.
  • Test the gas sensing properties of the 2D heterostructures

Methodology

  • Graphene growth on 4H- and 6H-SiC substrates by high temperature annealing in ultrahigh vacuum (UHV),
  • Graphene growth by high temperature annealing in Ar atmosphere.
  • Synthesis of MoS2 and WS2 on graphene/SiC by Chemical Vapour Deposition (CVD)
  • Synthesis of lateral heterostructures of graphene and h-BN by chemical conversion of graphene from ammonia (NH3) and boric acid (H3BO3) vapours in a horizontal tube furnace.
  • Scanning Tunneling Microscopy and spectroscopy studies of the surface reconstruction of the 2D heterostructures
  • Composition analysis of the heterostructures by Xray-Photoelectron Spectroscopy and Raman microscopy
  • Patterning nucleation sites by selectively inducing defects using an STM tip, or Helium Ion Litography to create induce of h-BN growth at specific locations

The specific activities will be tailored to the level of the student (V-RES, Honours, Master, PhD)  and to the available time. The student will work in an exciting, well-established, highly collaborative research group environment, using the most advanced instrumentation available at CARF, providing the opportunity for an effective and rich learning experience.

The team includes Prof. Nunzio Motta, expert in 2D materials for energy storage and in surface science, Dr Jennifer MacLeod, expert in surface science, molecular self assembly of 2D materials and graphene and an excellent group of PhD students and Post docs. The student will also benefit of an outstanding collaboration network including QUT researchers and international scientists.

The world-class facilities and the high level research environment available at QUT will provide me the essential tools to undertake these studies, which are at the cutting edge of the nanotechnology research.

Outcomes

This project aims at enabling integrated nanoelectronics devices with very high energy efficiency by exploiting the unique properties of two dimensional materials directly grown on silicon wafers.

Outcomes of the project will include:

  • Development of original approach to grow 2D heterostructures
  • Development of the fundamental building block for new nanoelectronic devices
  • Development of new low-power gas sensing devices

Skills and experience

  • Motivation and interest in scientific problems are required.
  • Strong foundations in Physics, Chemistry or Engineering is mandatory.
  • Specific skills will depend on the level of the project (VRES, Honours, Master, PhD).

Keywords

Contact

Contact the supervisor for more information.