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Diamond optoelectronic devices: switching diamond by light

Study level

PhD

Master of Philosophy

Honours

Faculty/Lead unit

Topic status

We're looking for students to study this topic.

Supervisors

Dr Dongchen Qi
Position
Senior Lecturer
Division / Faculty
Science and Engineering Faculty

Overview

Beyond its allure as a precious gemstone, diamond is regarded as an excellent material for electronic and optical applications, owing to a range of extraordinary material properties. Although diamond is highly insulating in its bulk, its surface, once terminated by hydrogen, can develop an intriguing p-type surface conductivity which can be rationally tailored by interfacing diamond with other materials. The two-dimensional hole gas (2DHG) on diamond surface, which supports the surface conductivity, also exhibits many interesting quantum properties that can be harvested for device applications. The diamond conducting surface, which can be tuned or functionalised by surface adsorbates, thus provides a versatile platform for building multifunction surface electronic and sensing devices.

While diamond surface conductivity can be easily tuned via charge transfer doping or by external electrostatic field (via gating), optical control of diamond surface electrical transport properties has yet been achieved. The principal aim of this project is to explore optical modulation of the diamond surface conducting channel by coupling rationally designed photochromatic molecules, molecules that are able to change their configurations upon light exposure, on diamond surface. This study will provide significant insights to the development of multi-functional diamond-based opto-electronic devices, and you will be exposed to multidisciplinary fields and equipped with experience in utilising state-of-the art characterisation tools and device fabrication.

Research activities

  • Study of the optical switching behaviours and electronic structures changes for photochromatic molecules both in solution phase and solid film phase by UV-Vis spectrsocopy, x-ray/ultraviolet photoemission spectroscopy (XPS/UPS)
  • Deposition of photochromatic molecular films on hydrogen-terminated diamond (001) surface by spin-coating inside a golvebox or evaporation inside an ultrahigh vacuum system
  • Investigate electronic structures and energy level alignment before and after light irradiation by XPS/UPS
  • Scanning tunneling microscopy (STM) and spectroscopy (STS) studies of the atomic structures, localised electronic structures and morphology of molecules on diamond surface
  • Fabricate diamond hall-bar devices and deposit molecules on the devices
  • Investigate the electrical properties of the device in response to light in a in-situ optoelectronic characterisation system.
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 main supervisor of this project, Dr. Dongchen Qi, is an ARC Future Fellow and an expert in diamond surface science and devices. The student will also benefit of an outstanding collaboration network including QUT researchers and international scientists. The student will have access to the world-class facilities and the high level research environment available at QUT which provides essential tools  to undertake these studies, which are at the cutting edge of the nanotechnology research.

Outcomes

Outcomes of the project will include:

  • Development of diamond optoelectronic devices
  • Development of knowledge and skills in device fabrication and characterisation
  • Development of knowledge and skills in surface characterisation

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).

Scholarships

You may be able to apply for a research scholarship in our annual scholarship round.

Annual scholarship round

Keywords

Contact

Contact the supervisor for more information.