Jack Alexander-Webber: Engineering oxide interfaces for graphene electronics

posted 2 Aug 2017, 01:49 by info admin
Department of Engineering, University of Cambridge, United Kingdom

Reliable and controlled interfacing with conventional dielectrics or barrier films remains a critical issue for 2D materials. Early attempts to grow atomic-layer deposited (ALD) layers directly on graphene resulted in inhomogeneous film growth. However, frequently used seed layers can negatively affect the as-grown interface. Here we present a detailed study of ALD Al2O3 nucleation on chemical vapour deposited (CVD) graphene films. By optimizing precursor exposure to promote Al2O3 nucleation, we show high-quality, dense ALD films directly on graphene without the need for seed layers [1]. These techniques have been shown to be suitable to grow sub-nanometre Al2O3 tunnel junctions directly on graphene for spintronic devices [2]. Film thicknesses of 90nm can virtually eliminate gate hysteresis for CVD graphene-based field-effect devices [3]. In addition, unintentional doping is significantly reduced and the room temperature field-effect mobility of encapsulated devices greatly increases. These results are relevant for 2D materials integration with conventional thin film and ultra-large-scale integration technologies.

1. Aria et al. ACS Appl. Mater. Interfaces 8, 30564 (2016)
2. Martin et al. ACS Nano 8, 7890 (2014)
3. Alexander-Webber et al. 2D Materials 4, 011008 (2017)

Jack Alexander-Webber holds Research Fellowship from the Royal Commission for the Exhibition of 1851 and is a Junior Research Fellow of Churchill College Cambridge. He graduated from Royal Holloway, University of London in 2009 with an MSci in Physics. After a summer studentship working for the National Physical Laboratory he began his DPhil in the group of Prof Robin Nicholas at the University of Oxford. His doctoral research was on the properties of low-dimensional nanostructures such as graphene, carbon nanotubes and III-V semiconductors with a particular focus on high magnetic field effects studied both in Oxford and at the European Magnetic Field Laboratory facilities in Grenoble and Toulouse. After completing his DPhil in 2013, Jack undertook an EPSRC Doctoral Prize fellowship at Oxford. He is currently working in the group of Prof Stephan Hofmann in the Department of Engineering at the University of Cambridge. His current research interests lie in developing scalable techniques to integrate low-dimensional nanomaterials in electronic and optoelectronic device applications.