Quantum technology capital: Multi-species single-ion implantation

量子技术对单原子的利用是真空中单原子和单离子电磁阱的最新进展。固体中的掺杂剂提供了一种天然的捕获形式，因为杂质被其周围的主体固体的电磁场保持在适当的位置，但在长度尺度上更小。一些固体，如硅，可以以惊人的纯度制成，每100，000，000，000份中有1份。这是如此纯净，纳米级器件可以预期具有零无意杂质，并且如果掺杂被仔细控制，则可以用单个孤立杂质原子构建器件，从而为固态QT开辟了丰富的可能性。这给本地环境的工程设计带来了新的挑战，但它们是健壮的、可再现的QT应用程序的理想对象。单掺杂剂为时钟、传感器和计算提供量子信息的“量子比特”，为量子密钥分配系统、量子中继器、量子光刻、多价逻辑和局部传感提供非经典光源。半导体中单个杂质的第一次电子观测是在冷却到约30 K的MOSFET器件中进行的--单个、自然产生的，靠近导电沟道的未识别的杂质产生随机电报噪声。单电子晶体管通道现在允许特定的附近的掺杂剂，以确定其对电气特性的影响。在某些情况下，单一的杂质可以用扫描隧道显微镜尖端以纳米精度掺入，但原则上，离子注入可以实现更大的多样性。离子注入是一种微电子工业标准技术，萨里大学设有英国国家离子束中心。虽然已经报道了具有约20 nm的横向精度的注入，但是以前仅可能使用光刻产生的掩模。这已经被用来制造有源器件，其中硅中的两个磷原子足够接近，以便它们的自旋在触发器相互作用中交换，但是这种器件的功能受到注入技术有限精度的限制，并且它没有被复制。一种更可扩展、可重复的技术是使用高度聚焦的离子束，但这需要注入工具的显著进步。该提案是安装世界上第一台具有20 nm横向束聚焦的单离子注入工具，能够从气体或固体源注入任何物质。该工具将满足英国对QTs学术界和工业界开放获取用户设施的需求。使用该工具，我们将能够在硅中注入单个铋原子，在金刚石中注入单个氮原子，在蓝宝石中注入单个铒原子，在GaAs中注入单个锰原子。每一个都是一个不同的QT平台，涵盖了从磁力测量到成像、计算和单光子发射的应用。我们将通过与关键合作伙伴（在金刚石NV的情况下）或内部（在Si中的Bi的情况下）的合作来表征和成像单原子器件。在Si：Bi（和其他硅浅杂质）的情况下，我们将安装一个世界领先的近场成像系统，使用太赫兹频率的光。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).