Giorgio Ferrari and Filippo Guagliardo published in "Nature Nanotechnology" the results of a major research done in collaboration with the Institute for Microelectronics and Microsystems of the National Research Council (CNR-IMM) and the Waseda University in Tokyo.
The team has fabricated transistors by 'shooting' at controlled positions single atoms of arsenic inside a silicon crystal. The unparalleled control of the electronic properties obtained using this technique has allowed to examine fundamental physical phenomena and it represents a step towards the realization of a new class of transistors smaller, faster and more efficient than existing ones.
The research was made possible thanks to the support of the Ministry of Foreign Affairs of Italy and the MEXT (Ministry of Science and Technology) of Japan, which promote joint research between the two countries in information technology excellence.
The unprecedented precision achieved by the single-ion implantation technique has allowed to observe a radical transition in the quantum transport of electrons inside the transistor when the number of donor atoms is increased from two to six. The experiment provides the most direct demonstration of impurity band formation in semiconductors at low temperatures and it extends previous achievements in the physics of individual donors to arrays of few donors for which collective phenomena (previously only studied with macroscopic numbers of atoms) clearly emerge.
Further information about these results is available at:http://www.cnr.it/cnr/news/CnrNews?IDn=2437
The paper published in “Nature Nanotechnology” is available at:http://www.nature.com/nnano/journal/v7/n7/full/nnano.2012.94.html