A highly promising route to scale millions of qubits is to use quantum photonic integrated circuits (PICs), where deterministic photon sources, reconfigurable optical elements, and single-photon detectors are monolithically integrated on the same silicon chip. The isolation of single-photon emitters, such as the G centers and W centers, in the optical telecommunication O-band, has recently been realized in silicon. In all previous cases, however, single-photon emitters were created uncontrollably in random locations, preventing their scalability. Here, we report the controllable fabrication of single G and W centers in silicon wafers using focused ion beams (FIB) with high probability. We also implement a scalable, broad-beam implantation protocol compatible with the complementary-metal-oxide-semiconductor (CMOS) technology to fabricate single telecom emitters at desired positions on the nanoscale. Our findings unlock a clear and easily exploitable pathway for industrial-scale photonic quantum processors with technology nodes below 100 nm.

The use of self-assembly techniques may open new possibilities in scaling down electronic circuits to their ultimate limits. Deoxyribonucleic acid (DNA) nanotechnology has already demonstrated that it can provide valuable tools for the creation of nanostructures of arbitrary shape, therefore presenting an ideal platform for the development of nanoelectronic circuits. So far, however, the electronic properties of DNA nanostructures are mostly insulating, thus limiting the use of the nanostructures in electronic circuits. Therefore, methods have been investigated that use the DNA nanostructures as templates for the deposition of electrically conducting materials along the DNA strands. The most simple such structure is given by metallic nanowires formed by deposition of metals along the DNA nanostructures. Here, we review the fabrication and the characterization of the electronic properties of nanowires, which were created using these methods.

Silicon, a ubiquitous material in modern computing, is an emerging platform for realizing a source of indistinguishable single photons on demand. The integration of recently discovered single-photon emitters in silicon into photonic structures is advantageous to exploit their full potential for integrated photonic quantum technologies. Here, we show the integration of an ensemble of telecom photon emitters in a two-dimensional array of silicon nanopillars. We developed a top-down nanofabrication method, enabling the production of thousands of nanopillars per square millimeter with state-of-the-art photonic-circuit pitch, all the while being free of fabrication-related radiation damage defects. We found a waveguiding effect of the 1278 nm-G center emission along individual pillars accompanied by improved brightness compared to that of bulk silicon. These results unlock clear pathways to monolithically integrating single-photon emitters into a photonic platform at a scale that matches the required pitch of quantum photonic circuits.