John Shannon

Professor John Shannon


Professorial Research Fellow
FREng, DSc, PhD, C.Phys, F.Inst.P, MIEE, C.Eng
+44 (0)1483 689310
21 ATI 02

Academic and research departments

Advanced Technology Institute.

About

Research

Research interests

Publications

Miyajima Y, Adikaari A, Henley SJ, Shannon JM, Silva SRP (2008) Electrical properties of pulsed UV laser irradiated amorphous carbon,APPLIED PHYSICS LETTERS92(15)ARTN 1 AMER INST PHYSICS

Amorphous carbon films containing no hydrogen were irradiated with a pulsed UV laser in vacuum. Raman spectroscopy indicates an increase in the quantity of sp(2) clustering with the highest laser energy density and a commensurate reduction in resistivity. The reduction of resistivity is explained to be associated with thermally induced graphitization of amorphous carbon films. The high field transport is consistent with a Poole-Frenkel type transport mechanism via neutral trapping centers related to sp(2) sites which are activated under high fields. Decreasing the resistivity is an important feature for use of carbon as an electronic material. (C) 2008 American Institute of Physics.

Silva S. R. P., Carey JD, Chen G. Y., Cox D. C., Forrest R. D., Poa C. H., Smith R. C., Tang Y. F., Shannon J. M. (2004) Nanoengineering of materials for field emission display technologies,IEE Proceedings in Circuits, Devices and Systems51pp. 489-496

The holy grail in terms of flat panel displays has been an inexpensive process for the production of large area 'hang on the wall' television that is based on an emissive technology. Electron field emission displays, in principle, should be able to give high quality pictures with good colour saturation, and, if suitable technologies for the production of cathodes over large areas were to be made available, at low cost. This requires a process technology where temperatures must be maintained below 450/spl deg/C throughout the entire production cycle to be consistent with the softening temperature of display glass. In this paper we propose three possible routes for nanoscale engineering of large area cathodes using low temperature processing that can be integrated into a display technology. The first process is based on carbon nanotube-polymer composites that can be screen printed over large areas and show electron field emission properties comparable with some of the best aligned nanotube arrays. The second process is based on the large area growth of carbon nanofibres directly onto substrates held at temperatures ranging from room temperature to 300/spl deg/C, thereby making it possible to use inexpensive substrates. The third process is based on the use of excimer laser processing of amorphous silicon for the production of lithography-free large area three terminal nanocrystalline silicon substrates. Each route has its own advantages and flexibility in terms of incorporation into an existing display technology. The harnessing of these synergies will be highlighted together with the properties of the cathodes developed for the differing technologies.