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A single-ion implantation (SII) system combining a laser-cooled linear-Paul-trap ion source (LPT-IS) and a two-stage acceleration lens is being developed to produce an array of nitrogen vacancy (NV) centers, which have recently attracted significant attention as potential qubits. The fabrication of the NV center array requires repeated implantations of a single nitrogen molecule ion (N 2 +) from SII into a diamond specimen with an energy on the order of a 10-keV and spatial precision of several tens of nanometers or less. To satisfy this requirement, N 2 + ions with very low emittance must be selectively extracted from the LPT-IS. In this study, the selective extraction of N 2 + ions is investigated using a three-dimensional multiparticle simulation by varying magnitudes and temporal profile of the voltage applied to the end plate electrodes of a conventional LPT. The emittance of the N 2 + extracted from the LPT-IS is the lowest when N 2 + ion is at the leading end of an array of N 2 + and Ca+ ions in the string-like crystalline structure formed with sympathetic cooling. We show that a single N 2 + ion with required energy can be extracted from the array of N 2 + and Ca+ ions passing through the end plate electrode of the LPT-IS, without spoiling the emittance, by increasing the voltage applied to the end plate electrode at the precise required moment. [ABSTRACT FROM AUTHOR]

Special point defects in semiconductors have been envisioned as suitable components for quantum‐information technology. The identification of new deep centers in silicon that can be easily activated and controlled is a main target of the research in the field. Vacancy‐related complexes are suitable to provide deep electronic levels but they are hard to control spatially. With the spirit of investigating solid state devices with intentional vacancy‐related defects at controlled position, the functionalization of silicon vacancies is reported on here by implanting Ge atoms through single‐ion implantation, producing Ge‐vacancy (GeV) complexes. The quantum transport through an array of GeV complexes in a silicon‐based transistor is investigated. By exploiting a model based on an extended Hubbard Hamiltonian derived from ab initio results, anomalous activation energy values of the thermally activated conductance of both quasi‐localized and delocalized many‐body states are obtained, compared to conventional dopants. Such states are identified, forming the upper Hubbard band, as responsible for the experimental sub‐threshold transport across the transistor. The combination of the model with the single‐ion implantation method enables future research for the engineering of GeV complexes toward the creation of spatially controllable individual defects in silicon for applications in quantum information technology. [ABSTRACT FROM AUTHOR]

Abstract: We present recent developments in controlled single-ion implantation techniques. A low energy (14keV) ion-beam is used to produce shallow phosphorus implants in high-purity Si. Single atom control during implantation is achieved by monitoring on-chip p-i-n detectors, integrated within the device structure, while positional accuracy of 20nm is achieved via a nanolithographic resist mask. This technique has been used to implant only two phosphorus dopant atoms for use as charge-based Si:P quantum bits (qubits). Voltages applied to precisely aligned surface electrodes control the double-donor system, and dual single-electron transistors (SETs) provide readout with spurious signal rejection. Preliminary low temperature measurements on devices implanted with less than 10 dopant atoms demonstrate isolated charge transfer events. [Copyright &y& Elsevier]

Ge-vacancy complex, Hubbard model, point defects, quantum transport, single-ion implantation Keywords: Ge-vacancy complex; Hubbard model; point defects; quantum transport; single-ion implantation EN Ge-vacancy complex Hubbard model point defects quantum transport single-ion implantation 1 1 1 05/26/21 20210521 NES 210521 In article number, 2011175, Simona Achilli, Enrico Prati, and co-workers report on the controlled creation of individual vacancies in silicon by implanting Ge atoms via single ion implantation, the quantum transport model of a disordered 1D array of Ge-V complexes, and its experimental characterization. Single-Ion Implantation: Position-Controlled Functionalization of Vacancies in Silicon by Single-Ion Implanted Germanium Atoms (Adv. Funct. [Extracted from the article]