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Fabrication of Quantum clock device integrated in silicon platform

Single atom based devices shows transport characteristics modulated by the quantum state of single dopant atoms located near the channel of the device. The manipulation of electrons’ spin, bound to a single donor, represents a solid platform for quantum information processing. In this thesis activity the design and fabrication of a nanometric transistor on a silicon-on-insulator substrate (SOI) will be realized by a combination of electron beam lithography and reactive ion etching tools. The heavily doped source and drain contacts and an intrinsic channel will be optimized using a spin on dopant procedure. This research project originated from the collaboration between the Australian group of the prof. Jamieson in Melbourne and Dr. Bollani in LNESS, will be based  on the capability of the Jamieson’s group to implant individual atoms with nanometric resolution, and this collaboration will require a continuous feedback with the Australian group through Skype call and exchange of samples. Considering the theoretical published work in the literature, the obtainment of a frequency standard is fundamental: it can be achieved thanks to a stable transition energy which acts as an ultraprecise clock. The transition must be stable and controllable and as independent as possible from external parameters. In the case of implanted bismuth atoms in silicon, the energies of certain transitions are almost independent from the external magnetic field, the ground and the first excited states represent a transition which energy, and thus frequency, are independent from magnetic field. This transition represents the abovementioned clock transitions. Even though bismuth hasn’t been employed for quantum clocks applications yet, it seems promising due to its energy levels stability. This thesis will consider that the realization of multiple gates on both the Si channel and the implanted region, in order to select the working regime of the transistor and to tune the energy level of implanted donors respectively, can be a successful approach to the optimization of a quantum clock.

This activity will be carried out in LNESS laboratory, Como,
Responsabile : Dr. Monica Bollani,
ufficio: 031 3327356 , laboratorio LNESS, via Anzani 42 , Como.