We demonstrate a method for the controlled implantation of single ions into a silicon substrate with energy of sub-20-keV. The method is based on the collection of electron-hole pairs generated in the substrate by the impact of a single ion. We have used the method to implant single 14-keV 31 P ions through nanoscale masks into silicon as a route to the fabrication of devices based on single donors in silicon.

COMMUNICATION (1 of 8)Diamond materials are central to an increasing range of advanced technological demonstrations, from high power electronics to nanoscale quantum bioimaging with unprecedented sensitivity. [1] However, the full exploitation of diamond for these applications is often limited by the uncontrolled nature of the diamond material surface, which suffers from Fermi-level pinning and hosts a significant density of electromagnetic noise sources. [2] These issues occur despite the oxide-free and air-stable nature of the diamond crystal surface, which should be an ideal candidate for functionalization and chemical engineering. In this work, a family of previously unidentified and near-ubiquitous primal surface defects, which are assigned to differently reconstructed surface vacancies, is revealed. The density of these defects is quantified with X-ray absorption spectroscopy, their energy structures are elucidated by ab initio calculations, and their effect on near-surface quantum Many advanced applications of diamond materials are now being limited by unknown surface defects, including in the fields of high power/ frequency electronics and quantum computing and quantum sensing. Of acute interest to diamond researchers worldwide is the loss of quantum coherence in near-surface nitrogen-vacancy (NV) centers and the generation of associated magnetic noise at the diamond surface. Here for the first time is presented the observation of a family of primal diamond surface defects, which is suggested as the leading cause of band-bending and Fermi-pinning phenomena in diamond devices. A combination of density functional theory and synchrotron-based X-ray absorption spectroscopy is used to show that these defects introduce low-lying electronic trap states. The effect of these states is modeled on band-bending into the diamond bulk and it is shown that the properties of the important NV defect centers are affected by these defects. Due to the paramount importance of near-surface NV center properties in a growing number of fields, the density of these defects is further quantified at the surface of a variety of differently-treated device surfaces, consistent with best-practice processing techniques in the literature. The identification and characterization of these defects has wide-ranging implications for diamond devices across many fields.

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Recently, Greiner et al. [ Nat. Mater. 2012, 11 , 76 ] published a survey of the level alignment of about 40 metal oxide/organic molecule interfaces. They observed a striking regularity in the electronic level alignment of the highest occupied molecular orbital (HOMO) and the Fermi level that depends solely on the difference between the substrate work function and the ionization energy of the molecule independent of the details of the electronic structure of the oxide. The authors could reproduce their data under the assumption of thermodynamic equilibrium occupation of the HOMO using four adjustable parameters. A model that quantifi es well-established concepts in heterojunction physics and achieves the same result without any adjustable parameters is presented here. This approach explains why the level alignment is rather independent of the experimental details, such as the electronic structure of the oxide, defects in the oxide, and the thickness of oxide and overlayer. are not included in the spectroscopically determined HOMO and LUMO energies as expressed through IE org and EA org , respectively. The unusually large polaronic binding energy is, according to the authors, due to the fact that one is dealing here with interface polarons. We shall return to this question later.Recently, Greiner et al. [ 29 ] expanded the results of Salaneck and co-workers [ 26 ] to encompass small molecules as well. They too observed the upper part of the Zorro curve for a great number of organic/metal oxide molecule interfaces, albeit measured slightly differently. Instead of the work function, they measured the energy of the HOMO orbital relative to E F , (i.e., the hole-emission barrier Φ Bp ), and plotted Δ E H = Φ Bp = E F -E HOMO vs. Φ sub -IE org . This plot is redrawn here as Figure 2 . Substrates and interfaces were prepared in UHV and the substrate work function, the ionization energy of the organic molecules, and Δ E H were measured in situ by photoemission spectroscopy. In this sense, Greiner et al.'s [ 29 ] procedure follows more closely that of Kahn and co-workers, [ 27 ] except for using metal substrates with a well-defi ned oxide layer on top. Nevertheless, the experimental results comply perfectly with those of Salaneck and co-workers and the interpretation is based on the same concept, namely the transition from the Schottky-Mott regime to pinning when the substrate work function equals the ionization energy:The transition at Φ sub -IE org = 0, as suggested by the dashed line, indicates that the relevant ICT + is indeed the HOMO. However, spectroscopically the HOMO is measured about 0.3 eV below E F . Greiner et al. [ 29 ] were able to describe their considerable body of data with an expression that contains four adjustable parameters. In what follows, we present a the electron affi nity and ionization energy of the organic semiconductor, respectively, as they are measured for the isolated constituents of the interface. This, of course, presupposes that the LUMO and HOMO are the transport levels for electrons a...