Academic Profiles

Research Interests

UPDATED PhD positions currently available 

Current research interests include (with links to publications)

1. Graphene and 2D Materials: band gap engineering, doping and characterization: We are studying the electronic, transport and doping of graphene and bilayer graphene in order to control the carrier concentration and induce an electronic and optical band gap. We also aim to understand charge transfer in the graphene - molecule  system which is important for graphene molecular sensors. 

  • Ab initio density functional theory (DFT) calculations of molecular doping of bilayer graphene (BLG). See our latest publication (March 2013) in ACS Nano on band gap engineering and opening up an electrical band gap of up to 150 meV in BLG using molecular dopants. We also show selective optical absorption in the 3-5 μm region of the spectrum and could be important for graphene photodetectors. 
  • Electrical and Raman characterisation of low substrate temperature (415oC) photothermal chemical vapour deposition of graphene on Cu. Using an optical source it is possible to efficiently couple energy into the metal catalyst growth surface while the substrate is held at over 250oC lower in temperature. We have also applied photothermal CVD to the growth of CNT forests with low electrical resistance for possible interconnect applications.
  • We are also looking at phonon effects, phonon dispersion curves, electron phonon coupling and band structure in 2D layered materials including graphene and silicene.

2. Metallic nanoparticles for high frequency electronics and antennas: We are interested in high frequency electrical conduction and have explored the high frequency characterization, up to 220 GHz, of low temperature processed metal nanoparticles. We have shown, published in ACS Applied Materials in December 2012, that the high frequency electrical losses of screen printed mm-long coplanar waveguide structures of metallic nanoparticles are lower than that of conventional thick-film paste micron-sized silver grains. The improved response is due to the better packing and the smoother surface. AFM measurements show that silver nanoparticles have about 1/3 the rms roughness compared to the micron-sized silver grains. The use of metallic nanoparticles in this way may offer a route to efficient, flexible conformal antennas.

3. Carbon Nanotube Processing and CNT-Polymer Composites for Large Area Electronic Applications: 

  • (NEW Dec. 2013). In collaboration with the UK's National Physical Laboratory, we have been looking at cavitation effects in the dispersion and controlled length reduction of nanotubes.  In this study, published in J. Phys. Chem. B, we distinguish between stable cavitation, which leads to chemical modification of the surface of the CNTs, and inertial cavitation, which favors CNT exfoliation and length reduction. Efficient dispersion of CNTs in aqueous solution is found to be dominated by mechanical forces generated via inertial cavitation, which in turn depends critically on surfactant concentration.
  • See our press release on high frequency (up to 220 GHz) applications of carbon nanotube polymer composites, which was published in Applied Physics Letters in October 2011, and showed low electrical losses (0.15 dB/mm) are possible in electrical conductors made from CNT-PMMA composites up to 25 mm in length. 
  • Our study of field emission from CNT-polymer composites, published in Small in 2009, has attracted considerable attention as it shows the importance of chemical functionalisation for efficient nanotube dispersion to minimize material wastage while retaining excellent electrical characteristics. Its impact is seen in several of areas of carbon nanotube engineering, including composite manufacture, large area transparent conductors and displays.
  • Both topics rely on how knowledge of functional materials processing can be used to tailor specific, in this case electrical, properties for large area applications. 

4. Current diamond-like carbon and carbon based electronics:  We continue to work on examining the electronic and transport properties of DLC with collaborators at the Indian Institute of Technology, Delhi and the National Physical Laboratory, Delhi looking at 

5. The structure, electrical transport and electronic properties of nanomaterials (with links to some papers) including

6. Rare Earth ion magnetic resonance (EPR) and Si optoelectronics: Previous projects included the first study of the EPR defects of Er3+ centres in oxygen co-implanted Si and the identification of the C1h monoclinic symmetry defect centre.  We explored how the Er3+:O ratio and Er3+:F ratio affected the ESR and photoluminescence properties in Si. A variety of ESR active centres with monoclinic C1h point group symmetry and trigonal symmetry were found.  This work was followed up by an examination of the validity of the cubic crystal field approximation for trigonal and tetragonal symmetry erbium 3+ centres.

 

7. Commercial applications of nanomaterials and societal impact Nanomaterials in general and carbon nanotubes and graphene, nanomaterials for high frequency applications in particular.

PhD positions are available to highly qualified candidates in all of the above areas, especially in graphene and high frequency characterisation of nanomaterials.

Teaching

Current or recent lecture courses
1. Nanoelectronics and Devices (EEEM022) to MSc students (FHEQ 7).

2. Nanoscience and Nanotechnology (EEE3025) to year 3 undergraduate students (FHEQ 6).

3. Digital Engineering and Integrated Circuits (EEE2034) to year 2 undergraduate students (FHEQ 5)

 

Past modules include

1.  Electronic Devices and Integrated Circuits (Year 2/FHEQ 5).

2.  Introduction to Computer Logic (Year 1/FHEQ 4).

Departmental Duties

PhD Research Positions

For a PhD position you will normally require a good Honours degree or MSc in Electronic Engineering, Physics or Materials. Current PhD positions include

1. Graphene electronics and band gap engineering: This project will use ab initio density functional theory to examine the electronic properties of graphene and related materials such as bilayer graphene in the presence of atoms and molecules. The project will examine how adsorption induces changes the carrier concentration (doping) of graphene and identify donor or acceptor behaviour; how the electronic and optical band gap depends on the type of species adsorbed and their concentration and how the electronic properties such band structure, density of states and transport properties change with adsorption.

2. Electronic and Structural Properties of 2D Nanomaterials: This project will use ab initio density functional theory to examine the electronic properties of 2D layered materials such as graphene, silicene, germanene, stanene and MoS2 and related materials.  The project will calculate the electronic properties such band structure and the density of states and how they will change adsorption. The project will also examine the interaction between electrons and phonons in these materials. 

3. Applications of Carbon Nanotube and Graphene Composites:  This project aims to study the electronic properties of carbon nanotube (CNT) and graphene composite materials. The project will explore how the type and concentration of material and chemical functionalisation can change the electronic properties of the composite; how the high field electrical behaviour changes with nanotube volume fraction and how the electrical breakdown of the composite depends on the nanotube content. 

See PhD project list here for more information.  Both experimental and theoretical projects in the areas of graphene, bilayer graphene and other layered materials; high field and high frequency characterization of nanomaterials. 

Other information

  • Fellow of the Institute of Nanotechnology, Fellow of the Higher Education Academy.
  • Member of the Institute of Physics, Member of Institute of Engineering Technology, Member of the American Physical Society.
  • Member of the EPSRC Peer Review College (2003 - present); recent EPSRC Panel Member (2012) and Panel Chairman (2013).
  • Referee Acknowledgment from the Editor, the Associate Editors and the Editorial Board Members of Applied Physics Letters (2012).
  • Member of the Committee of Visitors to the Division of Materials Research, US National Science Foundation (2011).
  • MSc External Examiner, University of Ulster (2011 - present).
  • Guest editor of the Journal of Material Science:Materials in Electronics volume 17, number 6, published in June 2006 on carbon based electronics.                               

Contact Me

E-mail:
Phone: 01483 68 6089

Find me on campus
Room: 17 ATI 02

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Publications

Here is a list of some recent research papers with links; a more complete list of peer-reviewed publications can be found via the Google Scholar website.

  1. Influence of Acoustic Cavitation on the Controlled Ultrasonic Dispersion of Carbon Nanotubes, Achilleas Sesis, Mark Hodnett, Gianluca Memoli, Andrew John Wain, Izabela Jurewicz, Alan B. Dalton, J David Carey, and Gareth Hinds, J. Phys. Chem. B 117, 15414 (2013).
  2. Molecular Doping and Band Gap Opening of Bilayer Graphene, Alexander J. Samuels and J. David Carey, ACS Nano 7, 2790 (2013). Local copy available here.
  3. Efficient coupling of optical energy for rapid catalyzed nanomaterial growth: High quality carbon nanotube synthesis at low substrate temperatures, Muhammad Ahmad, Jose V. Anguita, Vlad Stolojan, J. David Carey and S. Ravi P. Silva, ACS Appl. Mater. Interfaces, 5, 3861 (2013).
  4. Influence of Silver Incorporation on the Structural and Electrical Properties of Diamond-Like Carbon Thin Films, Neeraj Dwivedi, Sushil Kumar, J. David Carey, R. K. Tripathi, Hitendra K. Malik and  M. K. Dalai, ACS Appl. Mater. Interfaces 5, 2725 (2013). Local copy available here.
  5. Enhanced Electrical Conductivity of Silver Nanoparticles for High Frequency Electronic Applications, Ali H. Alshehri, Malgorzata Jakubowska, Anna Młożniak, Michal Horaczek, Diana Rudka, Charles Free and J. David Carey, ACS Appl. Mater. Interfaces 4, 7007 (2012). Local copy available here.
  6. Photoconductivity and Characterization of Nitrogen Incorporated Hydrogenated Amorphous Carbon Thin Films, Neeraj Dwivedi, Sushil Kumara, J. D. Carey, Hitendra K. Malik and Govind, J. Appl. Phys.112, 113706 (2012). Local copy available here.
  7. Structural and Electronic Characterization of Nanocrystalline Diamond-Like Carbon Thin Films, Neeraj Dwivedi, Sushil Kumara, R. K. Tripathi, J David Carey, Hitendra K. Malik and M. K. Dalai, ACS Appl. Mater. Interfaces 4, 5309 (2012). Local version available here.
  8. Photo-thermal chemical vapor deposition growth of graphene, Y.Y. Tan, K.D.G.I. Jayawardena, A.A.D.T. Adikaari, L.W. Tan, J.V. Anguita, S.J. Henley, V. Stolojan, J.David Carey, S.R.P. Silva, Carbon 50, 668 (2012). Local version available here.
  9. Electrical Performance of Carbon Nanotube – Polymer Composites at Frequencies up to 220 GHz, Ali H. Alshehri, Malgorzata Jakubowska, Marcin Sloma, Michal Horaczek, Diana Rudka, Charles Free and J. David Carey, Appl. Phys. Lett. 99, 153109 (2011). Local version available here.
  10. Field effect in chemical vapour deposited graphene incorporating a polymeric gate dielectric, Y. Y. Tan, L. W. Tan, K. D. G. I Jayawardena, J.V. Anguita, J. D. Carey and S. R. P. Silva, Synthetic Metals 161, 2249 (2011)
  11. Exact equipotential profile mapping: A self-validating method, L.D. Filip, J. David Carey and S.R.P. Silva, J. Appl. Phys. 109, 084527 (2011). Local version available here.
  12. Carbon Nanotube – Polymer Nanocomposites for Field Emission Cathodes, Thomas Connolly, Richard C. Smith, Yenny Hernandez, Yurii Gun’ko, Jonathan N. Coleman and J. David Carey, Small 5, 826 (2009). Local version available here.
  13. Two-step electron tunnelling from confined electronic states in a nanoparticle, L.D. Filip, M. Palumbo, J. David Carey, S.R.P. Silva, Phys. Rev B 79, 245429 (2009). Local version available here
  14. Improving the Field Emission from Carbon Nanotubes through Chemical Functionalisation: A Quantifiable Approach, J David Carey, J. Nanosci. Nanotech. 9, 6538 (2009).
  15. Molecular physisorption on Graphene and Carbon Nanotubes: A comparative ab initio study, Daniel Henwood and J. David Carey, Molecular Simulation 34, 1019 (2008).  Local version available here.
  16. Ab initio investigation of molecular hydrogen physisorption on graphene and carbon nanotubes, Daniel Henwood and J. David Carey, Phys. Rev. B 75, 245413 (2007). Local version available here.

Book Chapters and Review Articles

  1. Effects of nanoscale clustering in amorphous carbon, David Carey and Ravi Silva, Carbon: The Future Material for Advanced Technology Applications, Springer Series Topics in Applied Physics, volume 100, pp 137-152 (March 2006).
  2. Nanostructured materials for field emission devices, J.D. Carey and S.R.P. Silva, CRC Handbook on Nanomaterials, Ed. Y. Gogotsi, (January 2006)

Research impact to Society

Nanotechnology and public perception and society. See, for example, presentation and round table discussion on Developments in Nanotechnology and Contemporary International Intervention in July 2012. 

Nanomaterials for High Frequency Electronics: See our press release on high frequency (up to 220 GHz) applications of carbon nanotube polymer composites, published in Applied Physics Letters in October 2011, and showed low electrical losses (0.15 dB/mm) are possible in electrical conductors made from CNT-PMMA composites up to 25 mm in length. 

Carbon Nanotube Polymer Displays: Our study of field emission from CNT-polymer composites, published in Small in 2009, has attracted considerable attention e.g. see Azonono.com and Nanotechwire.com as it highlights the importance of chemical functionalisation for efficient nanotube dispersion to minimize material wastage while retaining excellent electrical characteristics. Its impact is seen in several of areas of carbon nanotube engineering, including composite manufacture, large area transparent conductors and displays.

Radio Interview on Nanoscience and Nanotechnology: Check out a radio interview I did on nanotechnology and nanomaterials for The Naked Scientists.

 

PhD theses include 

Alex Samuels (2013), Molecular Doping of Graphene based Materials

Ali Alshehri (2013), Nanomaterials for rf and sub-THz Applications

YY Tan (2011), Growth and Electrical Properties of Chemical Vapour Deposited Low Dimensional sp2 Carbons

Lucian Filip (2009), Modelling of Field Emission and Tunnelling Processes for Carbon Nanotubes and Multilayered Structures

Gemma Kerr (2008), Nanomanipulation and In-Situ Electrical Characterisation of Nanowires

Daniel Henwood (2008), Characterising the Interactions of Low-dimensional Carbon Nanostructures with Molecules and Nanowires

 

MSc Theses include

V Samuthiravel, Introduction of a band-gap in bilayer graphene by the applications of an electric field
M W Iqbal, Current through network of carbon nanotubes for transparent electronics
Y-C Chang, The electronic properties of graphene
H Khalil, Carbon nanotube composite cathodes
N Roome, Charge transfer in graphene for sensing applications
S Babar, Transport in Ballistic Transistors
T Connolly, Carbon nanotube interaction with gas molecules
V Devendran, Electrical characterization of nanowires and related materials
A Garcia Gurddon, Electrical characterization of Carbon Nanomaterials
C Price, A DFT study of CO dissociation on transition metals platinum, palladium and gold
B Patel, Pattern formation in low dimensions
S Sayid, Modelling of low dimensional devices
C S Soon, Polydimethylsiloxane encapsulation of organic solar cells
N Woolger, Growth and Characterisation of Carbon Nanotube related Materials Produced by Arc Discharge
G Douglas, Order and disorder in cellular networks
G Grigoriadis, Local environment effects for ions in materials
K Pigiotis, Calculating energy levels in materials
S Tziortzis, Nanotechnology and cellular networks

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