Pure platinum nanostructures grown by electron beam induced deposition

Platinum has numerous applications in catalysis, nanoelectronics, and sensing devices. Here we report a method for localized, mask-free deposition of high-purity platinum that employs a combination of room-temperature, direct-write electron beam induced deposition (EBID) using the precursor Pt(PF3)4, and low temperature (≤400 C) postgrowth annealing in H2O. The annealing treatment removes phosphorus contaminants through a thermally activated pathway involving dissociation of H2O and the subsequent formation of volatile phosphorus oxides and hydrides that desorb during annealing. The resulting Pt is indistinguishable from pure Pt films by wavelength dispersive X-ray spectroscopy (WDS). © 2013 American Chemical Society

Localized deposition of pure platinum nanostructures

© 2014 IEEE. Localized deposition of pure platinum nanostructures was achieved using a combination of focused electron beam induced processing (FEBID) of an inorganic platinum precursor and low temperature annealing in water vapour. This technique enables fabrication of Pt nanostructures with high spatial resolution and purity, for applications in nanoelectronics, sensing devices and catalysis

Gas-mediated charged particle beam processing of nanostructured materials

Gas mediated processing under a charged particle (electron or ion) beam enables direct-write, high resolution surface functionalization, chemical dry etching and chemical vapor deposition of a wide range of materials including catalytic metals, optoelectronic grade semiconductors and oxides. Here we highlight three recent developments of particular interest to the optical materials and nanofabrication communities: fabrication of self-supporting, three dimensional, fluorescent diamond nanostructures, electron beam induced deposition (EBID) of high purity materials via activated chemisorption, and post-growth purification of nanocrystalline EBID-grown platinum suitable for catalysis applications. © 2014 SPIE

Localization of Narrowband Single Photon Emitters in Nanodiamonds

© 2016 American Chemical Society. Diamond nanocrystals that host room temperature narrowband single photon emitters are highly sought after for applications in nanophotonics and bioimaging. However, current understanding of the origin of these emitters is extremely limited. In this work, we demonstrate that the narrowband emitters are point defects localized at extended morphological defects in individual nanodiamonds. In particular, we show that nanocrystals with defects such as twin boundaries and secondary nucleation sites exhibit narrowband emission that is absent from pristine individual nanocrystals grown under the same conditions. Critically, we prove that the narrowband emission lines vanish when extended defects are removed deterministically using highly localized electron beam induced etching. Our results enhance the current understanding of single photon emitters in diamond and are directly relevant to fabrication of novel quantum optics devices and sensors

Charged Particle Induced Etching and Functionalization of Two-Dimensional Materials

Focused electron beam induced deposition and etching (FEBID and FEBIE) are direct-write nanofabrication techniques in which an electron beam is used to achieve nanostructure functionalization, etching or deposition. Either alone or in combination with in situ plasmas, these techniques can also be used to accelerate reactions that occur in ambient environment, with simultaneous high-resolution imaging. Here, we describe our recent work on etching, functionalization and directed assembly of a range of nanoand two-dimensional materials using temperature-dependent FEBIE experiments in an environmental scanning electron microscope (ESEM). As examples of the application of these techniques, we demonstrate processes for assembling arrays of nanodiamonds that can be used as magnetic field sensors, as well as for controlled etching of hexagonal boron nitride (hBN) and black phosphorus (BP)

Robust multicolor single photon emission from point defects in hexagonal boron nitride

© 2017 IEEE. We demonstrates engineering of quantum emitters in hBN multi-layers using either electron beam irradiation or annealing. The defects exhibit a broad range of multicolor room-temperature single photon emissions across the visible and the near-infrared ranges

Single photon emission from plasma treated 2D hexagonal boron nitride

© 2018 The Royal Society of Chemistry. Artificial atomic systems in solids are becoming increasingly important building blocks in quantum information processing and scalable quantum nanophotonic networks. Amongst numerous candidates, 2D hexagonal boron nitride has recently emerged as a promising platform hosting single photon emitters. Here, we report a number of robust plasma and thermal annealing methods for fabrication of emitters in tape-exfoliated hexagonal boron nitride (hBN) crystals. A two-step process comprising Ar plasma etching and subsequent annealing in Ar is highly robust, and yields an eight-fold increase in the concentration of emitters in hBN. The initial plasma-etching step generates emitters that suffer from blinking and bleaching, whereas the two-step process yields emitters that are photostable at room temperature with emission wavelengths greater than ∼700 nm. Density functional theory modeling suggests that the emitters might be associated with defect complexes that contain oxygen. This is further confirmed by generating the emitters via annealing hBN in air. Our findings advance the present understanding of the structure of quantum emitters in hBN and enhance the nanofabrication toolkit needed to realize integrated quantum nanophotonic circuits

Reforming Fiscal Institutions in Resource-Rich Arab Economies: Policy Proposals

This paper traces the evolution of fiscal institutions of Resource Rich Arab Economies (RRAEs) over time since their pre-oil days, through the discovery of oil to their build-up of oil exports. It then identifies challenges faced by RRAEs and variations in their severity among the different countries over time. Finally, it articulates specific policy reforms, which, if implemented successfully, could help to overcome these challenges. In some cases, however, these policy proposals may give rise to important trade-offs that will have to be evaluated carefully in individual cases