We demonstrate a method for the controlled implantation of single ions into a silicon substrate with energy of sub-20-keV. The method is based on the collection of electron-hole pairs generated in the substrate by the impact of a single ion. We have used the method to implant single 14-keV 31 P ions through nanoscale masks into silicon as a route to the fabrication of devices based on single donors in silicon.

We report on the demonstration of a silicon-based quantum cellular automata (QCA) unit cell incorporating two pairs of metallically doped (n+) phosphorus-implanted nanoscale dots, separated from source and drain reservoirs by nominally undoped tunnel barriers. Metallic cell control gates, together with Al–AlOx single electron transistors for noninvasive cell-state readout, are located on the device surface and capacitively coupled to the buried QCA cell. Operation at subkelvin temperatures was demonstrated by switching of a single electron between output dots, induced by a driven single electron transfer in the input dots. The stability limits of the QCA cell operation were also determined.

Local photocurrent mapping as a probe of contact effects and charge carrier transport in semiconductor nanowire devices J.