Scanning Probe and Point Projection Microscopies for Fundamental Nano-Science Studies

用于基础纳米科学研究的扫描探针和点投影显微镜

• 批准号: RGPIN-2014-05684
• 负责人: Wolkow, Robert
• 金额: $ 7.21万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567326
• 关键词: Scanning; Probe; Point; Projection; Microscopies

Scanning probe microscopes (SPMs) have been extraordinarily effective tools for elucidating properties inherent to the nano-scale. Further development and application of SPMs is central to our overall research program. Our proposed studies will gain further fundamental understanding of surface-confined nano-scale properties of silicon. Concepts like field controlled computing, FCC, a basis for extremely fast and low power classical computing have been transformed by our discovery that silicon dangling bonds (DBs), created by removal of single H atoms from an H-terminated silicon surface, serve as atomic silicon quantum dots. Previous implementations required extreme cryogenic conditions. Coupled DBs make FCC viable at room temperature. The subject of coupled DBs is in its infancy. As pioneers of the concept and due to our facilities, substantial re-tooling, and previous work and collaborations, we are ideally positioned to explore it. Our newly established and highly stable 4 Kelvin SPM (both scanning tunneling microscope, STM, and atomic force microscope, AFM) allows us to enter a new fabrication and measurement regime. An integral field ion microscope allows routine deployment of our nitrogen stabilized single atom tip as a scanned probe. A second 4 K instrument, with magnet, and radio frequency detection capabilities will soon be operational, allowing most ideal ever single spin electron spin resonance measurements. The spectroscopy of single and coupled DBs will inform classical and quantum computing studies. Coulomb blockading effects will become accessible. AFM force scans will provide a new perspective on charge distributions at DBs. Extraordinary new AFM sensors we have developed enhance our chances of success. Experimental study of inter-DB tunneling through current-voltage, IV, spectra, with close coupled models developed with collaborators, will yield strength of interaction (~100 meV at 2 nm separation is expected) critically informing models of information conveyance by DB ensembles. Knowledge of DB coupling strength will guide an extensive joint theoretical and experimental program with Barry Sanders at Calgary that will assess tunnel rate and coherence properties. We predict ~10e5 coherent oscillations may be completed before a decohering event. In collaboration with Hong Guo at McGill, and with a co-supervised student, we will extend our joint studies of surface state mediated transport. We aim to reveal the nature and magnitude of such surface transport channels, thereby settling some controversy, and furthermore expect to indicate the possibility of connecting future nano-devices in this unique way. Our home made multi-probe STM will enable these atom-scale transport studies. DB-based wires, tunnel gaps and single electron transistors of unprecedented uniformity will be explored. With Konrad Walus of UBC, who works with dWAVE, the maker of a quantum annealing computer, we have a unique program of study for FCC circuit optimization. Woven throughout the proposal are refinements and applications of our nano-tips. The tip is fabricated by a chemical and field assisted, spatially restricted etch that leaves all but the apex W atom nitride coated. Unlike coating-free sharp metal tips, ours are extremely robust. A coherent electron emission opening angle of >14 degrees has been achieved, compared to ~3 degrees for any previous source. We calculate that 0.2 nm holographic projection microscope resolution is now possible, compared to 1.5 nm previously. High resolution and low beam damage will allow biological molecules to be imaged. Phase change around nano-magnets will be accessible. Our training record is excellent. Our students will get and will create jobs directly related to this work.

扫描探针显微镜(SPM)已经成为阐明纳米级固有特性的非常有效的工具。进一步开发和应用SPM是我们整个研究计划的核心。我们提出的研究将进一步从根本上理解硅的表面受限纳米特性。我们的发现改变了场控制计算、FCC等概念，FCC是极快和低功耗经典计算的基础，我们的发现是，通过从H端的硅表面移除单个H原子而产生的硅悬挂键(DBs)作为原子硅量子点。以前的实施需要极端的低温条件。耦合的DB使催化裂化在室温下可行。耦合数据库的主题还处于初级阶段。作为这一概念的先驱，由于我们的设施、大量的改装以及之前的工作和合作，我们处于探索这一概念的理想位置。我们新建立的高度稳定的4Kelvin SPM(扫描隧道显微镜和原子力显微镜)使我们进入了一个新的制造和测量体系。集成场离子显微镜允许常规部署我们的氮稳定单原子尖端作为扫描探针。具有磁铁和射频检测能力的第二台4K仪器将很快投入使用，从而实现有史以来最理想的单自旋电子自旋共振测量。单DB和耦合DB的光谱将为经典和量子计算研究提供信息。库仑阻挡效果将变得可用。原子力显微镜的力量扫描将提供一个新的视角，在数据库中的电荷分布。我们开发的非凡的新型AFM传感器增加了我们成功的机会。利用与合作者共同开发的紧密耦合模型，对通过电流-电压光谱的DB间隧道传输的实验研究，将产生相互作用强度(约100 meV，间隔2 nm)，为DB系综的信息传输模型提供关键信息。对DB耦合强度的了解将指导与Barry Sanders在卡尔加里进行的广泛的联合理论和实验计划，该计划将评估隧道速率和相干特性。我们预测~10e5相干振荡可能在退色散事件之前完成。通过与麦吉尔大学的郭红和一名共同指导的学生的合作，我们将扩展我们对表面态介导的输运的联合研究。我们的目标是揭示这种表面传输通道的性质和大小，从而解决一些争议，并进一步指出以这种独特的方式连接未来纳米设备的可能性。我们自制的多探针扫描隧道显微镜将使这些原子尺度的输运研究成为可能。将探索基于DB的导线、隧道间隙和具有前所未有的一致性的单电子晶体管。与UBC的康拉德·沃卢斯(Konrad Walus)合作，我们有了一个独特的FCC电路优化研究计划。整个提案贯穿着我们对纳米尖端的改进和应用。尖端是由化学和场辅助的空间受限蚀刻制成的，除了顶端的W原子氮化物外，其余都被覆盖。与无涂层的锋利金属尖端不同，我们的尖端非常坚固。相干电子发射开口角已经达到&gt；14度，而以前的任何源都是~3度。我们计算出，与以前的1.5纳米相比，现在可以实现0.2纳米的全息投影显微镜分辨率。高分辨率和低光束损伤将使生物分子得以成像。纳米磁体周围的相变将是可获得的。我们的训练记录非常好。我们的学生将获得并将创造与这项工作直接相关的就业机会。