Nano-scale modification and doping of diamond: interesting science and promising technology

Diamond is a unique material with outstanding physical and chemical properties. Among these are very unusual properties of the diamond surface; i.e., its negative electron affinity when hydrogen terminated (i.e., 'negative work-function') and the p-type 2D electrical conductivity it shows (when exposed to different atmospheres). These make diamond a material of choice for the fundamental study of a variety of electron-emission processes as well as for their application, on the nano-scale, as point cold electron-emission devices and various nano-size electronic devices. The uniqueness of the diamond surface, when hydrogen terminated are discussed. Results on the emission of electrons from diamond induced by an external electric field (field emission) by electron-impact (secondary electron emission) and by ion-impact (ion-induced electron-emission) are reviewed. Modifications of these properties on the nano-scale by single ion-impacts and by localised electric fields (from a STM tip) are demonstrated. Stunning results on huge ion-induced electron emission and their rapid degradation are presented and explained. The possible application of the electron-emission from diamond utilising its 2D surface conductivity and the resulting quantisation are discussed enabling the realisation of low dimensional (line and point) devices including point sources of cold electrons and for nano scale electronic devices.