Electrically-detected magnetic resonance in ion-implanted Si:P   nanostructures
  We present the results of electrically-detected magnetic resonance (EDMR) experiments on silicon with ion-implanted phosphorus nanostructures, performed at 5 K. The devices consist of high-dose implanted metallic leads with a square gap, into which Phosphorus is implanted at a non-metallic dose corresponding to 10^17 cm^-3. By restricting this secondary implant to a 100 nm x 100 nm region, the EDMR signal from less than 100 donors is detected. This technique provides a pathway to the study of single donor spins in semiconductors, which is relevant to a number of proposals for quantum information processing. 
D. R. McCamey, H. Huebl, M. S. Brandt, W. D. Hutchison, J. C.   McCallum, R. G. Clark and A. R. Hamilton