Nanoscale electronic and optoelectronic materials & Scanning Probe Microscopy
The principle aim of my research is to build an understanding of important electronic and optoelectronic processes in nanoscale materials from the atomic scale up. In particular, the role of interfaces in organic and nanoscale materials is often of crucial importance for applications oriented processes, yet is frequently not fully understood. Scanning probe microscopy offers the ability to investigate such interfaces at the atomic level.
My research program makes use of scanning probe microscopy (SPM) techniques including atomic force microscopy (AFM) and scanning tunnelling microscopy (STM) in ultrahigh vacuum (UHV) and at low temperatures (~5K). This clean, low-temperature environment allows the characterization of well defined systems, with sufficiently high energy resolution for most organic and nanoscale systems of interest, and with the level of stability required to achieve measurements on individual nanostructures.
Organic thin film electronics
Organic thin film electronic and optoelectronic applications are emerging as exciting and promising technologies. However, there remain many questions, particularly regarding the influence of the device environment on the processes which give rise to the desired device functionality. In order to investigate the "organic film/gate dielectric" interface, prototype molecules on dielectric surfaces can be studied using non-contact AFM at the molecular/atomic scale to determine structure, as well as functionality through techniques such as Kelvin Probe Force Microscopy (KPFM). Also, the influence of different types of dielectric surfaces will be studied (e.g. ordered vs. amorphous surfaces) on the electronic structure and electrostatic environment on organic films and other nanomaterials such as graphene.
Through collaboration with other researchers, STM and nc-AFM techniques will be used to characterize prototype nanoscale photovoltaic (PV) materials to understand the role of interfaces in key processes in charge generation, separation and transport. SPM techniques combined with optical excitation and spectroscopy require continued innovation in order to address this difficult, but important aspect of the development of alternative PV materials for clean energy.
The development of techniques and progression of science go hand-in-hand. STM perhaps provides a particularly key example in that it helped to bring about the growth of nanoscience as an important new field in chemistry and physics as it made "seeing" at the nanoscale a reality. Conversely, the science STM enabled has pushed forward much of the development of STM and other scanned probe techniques. Technique development will be a key focus of my research, in particular towards improving understanding of KPFM on a variety of different materials and various modes of combined SPM-optical experiments.