Crystal defects in diamond have emerged as unique objects for a variety of applications, both because they are very stable and because they have interesting optical properties. Embedded in nanocrystals, they can serve, for example, as robust single-photon sources or as fluorescent biomarkers of unlimited photostability and low cytotoxicity. The most fascinating aspect, however, is the ability of some crystal defects, most prominently the nitrogen-vacancy (NV) center, to locally detect and measure a number of physical quantities, such as magnetic and electric fields. This metrology capacity is based on the quantum mechanical interactions of the defect's spin state. In this review, we introduce the new and rapidly evolving field of nanoscale sensing based on single NV centers in diamond. We give a concise overview of the basic properties of diamond, from synthesis to electronic and magnetic properties of embedded NV centers. We describe in detail how single NV centers can be harnessed for nanoscale sensing,...

Nitrogen-Vacancy Centers in Diamond: Nanoscale Sensors for Physics and Biology

Solid-state spin systems including nitrogen-vacancy (NV) centers in diamond constitute an increasingly favored quantum sensing platform. However, present NV ensemble devices exhibit sensitivities orders of magnitude away from theoretical limits. The sensitivity shortfall both handicaps existing implementations and curtails the envisioned application space. This review analyzes present and proposed approaches to enhance the sensitivity of broadband ensemble-NV-diamond magnetometers. Improvements to the spin dephasing time, the readout fidelity, and the host diamond material properties are identified as the most promising avenues and are investigated extensively. Our analysis of sensitivity optimization establishes a foundation to stimulate development of new techniques for enhancing solid-state sensor performance.

Sensitivity optimization for NV-diamond magnetometry

The burgeoning field of nanophotonics has grown to be a major research area, primarily because of the ability to control and manipulate single quantum systems (emitters) and single photons on demand For many years studying nanophotonic phenomena was limited to traditional semiconductors (including silicon and GaAs) and experiments were carried out predominantly at cryogenic temperatures In the last decade, however, diamond has emerged as a new contender to study photonic phenomena at the nanoscale Offering plethora of quantum emitters that are optically active at room temperature and ambient conditions, diamond has been exploited to demonstrate super-resolution microscopy and realize entanglement, Purcell enhancement and other quantum and classical nanophotonic effects Elucidating the importance of diamond as a material, this review will highlight the recent achievements in the field of diamond nanophotonics, and convey a roadmap for future experiments and technological advancements

/pdf/diamond-nanophotonics-3gpmuladxc.pdf

Diamond Nanophotonics

The past two decades have seen great advances in developing color centers in diamond for sensing, quantum information processing, and tests of quantum foundations. Increasingly, the success of these applications as well as fundamental investigations of light–matter interaction depend on improved control of optical interactions with color centers—from better fluorescence collection to efficient and precise coupling with confined single optical modes. Wide ranging research efforts have been undertaken to address these demands through advanced nanofabrication of diamond. This review will cover recent advances in diamond nano- and microphotonic structures for efficient light collection, color center to nanocavity coupling, hybrid integration of diamond devices with other material systems, and the wide range of fabrication methods that have enabled these complex photonic diamond systems.

Quantum nanophotonics in diamond [Invited]

One of the fundamental properties of semiconductors is their ability to support highly tunable electric currents in the presence of electric fields or carrier concentration gradients. These properties are described by transport coefficients such as electron and hole mobilities. Over the last decades, our understanding of carrier mobilities has largely been shaped by experimental investigations and empirical models. Recently, advances in electronic structure methods for real materials have made it possible to study these properties with predictive accuracy and without resorting to empirical parameters. These new developments are unlocking exciting new opportunities, from exploring carrier transport in quantum matter to in silico designing new semiconductors with tailored transport properties. In this article, we review the most recent developments in the area of ab initio calculations of carrier mobilities of semiconductors. Our aim is threefold: to make this rapidly-growing research area accessible to a broad community of condensed-matter theorists and materials scientists; to identify key challenges that need to be addressed in order to increase the predictive power of these methods; and to identify new opportunities for increasing the impact of these computational methods on the science and technology of advanced materials. The review is organized in three parts. In the first part, we offer a brief historical overview of approaches to the calculation of carrier mobilities, and we establish the conceptual framework underlying modern ab initio approaches. We summarize the Boltzmann theory of carrier transport and we discuss its scope of applicability, merits, and limitations in the broader context of many-body Green's function approaches. We discuss recent implementations of the Boltzmann formalism within the context of density functional theory and many-body perturbation theory calculations, placing an emphasis on the key computational challenges and suggested solutions. In the second part of the article, we review applications of these methods to materials of current interest, from three-dimensional semiconductors to layered and two-dimensional materials. In particular, we discuss in detail recent investigations of classic materials such as silicon, diamond, gallium arsenide, gallium nitride, gallium oxide, and lead halide perovskites as well as low-dimensional semiconductors such as graphene, silicene, phosphorene, molybdenum disulfide, and indium selenide. We also review recent efforts toward high-throughput calculations of carrier transport. In the last part, we identify important classes of materials for which an ab initio study of carrier mobilities is warranted. We discuss the extension of the methodology to study topological quantum matter and materials for spintronics and we comment on the possibility of incorporating Berry-phase effects and many-body correlations beyond the standard Boltzmann formalism.

https://iopscience.iop.org/article/10.1088/1361-6633/ab6a43/pdf

First-principles calculations of charge carrier mobility and conductivity in bulk semiconductors and two-dimensional materials

Diamond as an electronic material

Impedance spectroscopy has been used to investigate conductivity within boron-doped diamond in an intrinsic/delta-doped/intrinsic (i-d-i) multilayer structure. For a 5 nm thick delta layer, three conduction pathways are observed, which can be assigned to transport within the delta layer and to two differing conduction paths in the i-layers adjoining the delta layer. For transport in the i-layers, thermal trapping/detrapping processes can be observed, and only at the highest temperature investigated (673 K) can transport due to a single conduction process be seen. Impedance spectroscopy is an ideal nondestructive tool for investigating the electrical characteristics of complex diamond structures.

Multiple conduction paths in boron δ-doped diamond structures

Impedance spectroscopy has been used to investigate the conductivity displayed by diamond doped with boron in an intrinsic-δ-layer-intrinsic multilayer system with differing δ-layer thicknesses. Carrier transport within 5 nm δ-layer structures is complex, being dominated by conduction in the interfacial regions between the δ-layer and the intrinsic regions, as well as conduction within the δ-layer itself. In the case of 3.2 nm thick δ-layers the situation appears improved with uncapped samples supporting only two conduction paths, one of which may be associated with transport outside of the δ-layer, the other low transport within the δ-layer complex diamond structures. Introduction of the capping layer creates a third conduction path associated with unwanted boron in the capping layer-δ-layer interface.

An impedance spectroscopic investigation of the electrical properties of δ-doped diamond structures

Electronic field effect devices, and methods of manufacture of these electronic field effect devices are disclosed. In particular, there is disclosed an electronic field effect device which has improved electrical properties due to the formation of a highly mobile two-dimensional charge-carrier gas in a simple structure formed from diamond in combination with polar materials.

Electronic field effect devices and methods for their manufacture

A diamond semiconductor field effect transistor, comprising: an n-doped diamond backing layer 330, a diamond buffer layer 332 formed on the backing layer, p-doped source and drain diamond contact layer regions 310S, 310D on the buffer layer or in the surface of the buffer layer opposite to the backing layer, the contact layer regions being spaced apart by a gate portion 334 of the buffer layer by a gate length, a dielectric layer 318 formed across the gate portion of the buffer layer and partially extending over the contact layer regions to form the diamond-dielectric interface, source and drain electrodes 312, 314 electrically contacting the contact layer regions, and a gate electrode 320 is provided on the dielectric, wherein the gate portion of the buffer layer has a density of interface states of less than 2 x 1013 cm- 2 and methods of manufacturing such a transistor. The low density of interface states is produced by wet etching followed by oxygen termination.

Richard Stuart Balmer

Papers

Diamond as an electronic material

Multiple conduction paths in boron δ-doped diamond structures

An impedance spectroscopic investigation of the electrical properties of δ-doped diamond structures

Electronic field effect devices and methods for their manufacture

A diamond field effect transistor