Quantum technology capital: Multi-species single-ion implantation

单原子量子技术(QT)的开发是真空中单原子和单离子电磁陷阱的最先进技术。固体中的掺杂物提供了一种自然的捕获形式，因为杂质被周围的主体固体的电磁场固定在适当的位置，但长度尺度要小几个数量级。有些固体，例如硅，其纯度可以达到惊人的每100亿分之一。这是如此的纯净，以至于可以预期纳米级器件的无意杂质为零，如果仔细控制掺杂，可以用单个孤立的杂质原子构建器件，从而为固态QT提供了丰富的可能性。这给当地环境工程带来了新的挑战，但它们是健壮、可重现的Qt应用程序的理想对象。单掺杂为时钟、传感器和计算提供量子信息的量子比特，以及用于量子密钥分配系统、量子中继器、量子光刻、多价逻辑和局域传感的非经典光源。首次在冷却到约30K的MOSFET器件中对半导体中的单个杂质进行电子观测--靠近传导通道的单个自然发生的、未知的双稳杂质产生随机电报噪声。单电子晶体管通道现在允许通过它们对电特性的影响来识别附近的特定掺杂物。在某些情况下，单一的杂质可以用扫描隧道显微镜针尖以纳米级的精度结合，但原则上，通过离子注入可以实现更多种类的杂质。离子注入是微电子工业标准技术，萨里大学拥有英国国家离子束中心。虽然已经报道了横向精度约为20纳米的注入，但以前只有光刻制作的掩模才能做到这一点。这已经被用来制造涉及硅中两个磷原子的有源器件，这些器件足够近，以至于它们的自旋可以在触发器相互作用中交换，但这种器件的功能受到注入技术有限精度的限制，而且还没有被重现。一种更可扩展、可重复性更强的技术是使用高度聚焦的离子束，但这需要在注入工具方面取得重大进展。这项提议是安装世界上第一个具有20 nm横向光束焦点的单离子注入工具，能够从气体或固体源注入任何物种。该工具将满足英国学术界和工业界对QT开放访问用户设施的需求。使用该工具，我们将能够在硅中注入单一的铋原子，在钻石中注入单一的氮原子，在蓝宝石中注入单一的Er原子，在砷化镓中注入单一的锰原子。其中的每一个都体现了不同的QT平台，涵盖了从磁测量到成像、计算和单光子发射的应用。我们将通过与主要合作伙伴的合作(在钻石NV的情况下)或在内部(在Si中的铋的情况下)来表征和描绘单原子设备。在硅：铋(和其他硅浅杂质)的情况下，我们将安装世界领先的使用太赫兹频率光的近场成像系统。这将利用萨里与国家物理实验室(NPL)的战略合作伙伴关系。

The exploitation of single atoms for Quantum Technologies (QT) is most advanced for single-atom and single-ion electromagnetic traps in vacuum. Dopants in solids provide a natural form of trapping, as the impurity is held in place by the electromagnetic fields of the host solid around it, but on a length scale orders of magnitude smaller. Some solids, such as silicon can be made with an astonishing purity of 1 part per 100,000,000,000. This is so pure that nano-scale devices can be expected to have zero unintentional impurities and, if the doping is carefully controlled, a device can be constructed with a single, solitary impurity atom opening up a wealth of possibilities for solid state QT. This brings new challenges in engineering the local environment, but they are ideal objects for robust, reproducable QT applications. Single dopants provide 'qubits' of quantum information for clocks, sensors and computation, and non- classical light sources for quantum key distribution systems, quantum repeaters, quantum lithography, multivalent logic and local sensing.The first electronic observation of a single impurity in a semiconductor was made in a MOSFET device cooled to about 30K - the single, naturally occurring, unidentified bistable impurity close to the conduction channel produced random telegraph noise. Single electron transistor channels now allow specific nearby dopants to be identified by their effect on the electrical characteristics. In some cases single impurities may be incorporated with nanometre precision using Scanning Tunnelling Microscope tips, but a much greater variety could, in principle, be achieved with ion implantation. Ion implantation is a microelectronic industry standard technique, and Surrey University houses the UK National Ion Beam Centre. Although implantation with a lateral accuracy of about 20 nm has been reported, it has only previously been possible with lithographically produced masks. This has already been used to create active devices that involve two phosphorus atoms in silicon close enough for their spins to exchange in a flip-flop interaction, but the functionality of this device was restricted by the limited accuracy of the implantation technique, and it has not been reproduced. A much more scalable, reproducible technology would be to use highly focused ion beams, but this requires a significant advancement in implantation tools. This proposal is to install the world's first single ion implantation tool with 20nm lateral beam focus, with the ability to implant any species from gas or solid source. The tool will serve the UK need for an open access user facility for academia and industry in QTs.Using this tool, we will enable implantation of single bismuth atoms in silicon, single nitrogen atoms in diamond, single erbium atoms in sapphire, and single manganese atoms in GaAs. Each of these exemplifies a different QT platform and covers applications from magnetometry to imaging, computation and single photon emission. We will characterize and image the single atom devices, either via collaboration with key partners (in the case of diamond NV) or in house (in the case of Bi in Si). In the case of the Si:Bi (and other silicon shallow impurities) we will install a world leading near-field imaging system using terahertz frequency light. This will take advantage of Surrey's strategic partnership with the National Physical Laboratory (NPL).