Jamie S. Laird

Highly Luminescent Metal–Organic Frameworks Through Quantum Dot Doping

The incorporation of highly luminescent core-shell quantum dots (QDs) within a metal-organic framework (MOF) is achieved through a one-pot method. Through appropriate surface functionalization, the QDs are solubilized within MOF-5 growth media. This permits the incorporation of the QDs within the evolving framework during the reaction. The resulting QD@MOF-5 composites are characterized using X-ray fluorescence, cross-sectional confocal microscopy, energy-dispersive X-ray spectroscopy, scanning electron microscopy, and small-angle X-ray scattering. The synergistic combination of luminescent QDs and the controlled porosity of MOF-5 in the QD@MOF-5 composites is harnessed within a prototype molecular sensor that can discriminate on the basis of molecular size.

Development of a new data collection system and chamber for microbeam and laser investigations of single event phenomena

Abstract A new target chamber and control system for temperature-based transient-IBIC and transient-LBIC measurements using the same experimental chamber is outlined. The system has been designed for both ultra-fast and relatively slow transient measurements as a function of temperature from 77 K to 450 K. The control system, implemented in the Labview environment, allows single ion scanning and transient acquisition on a set of oscilloscopes, for an array of temperatures and bias. The modularity of the system allows its use for a broad range of experiments from single event upset transient current measurements to scanning ion deep level transient spectroscopy charge transient measurements. In this paper, we describe the overall system and illustrate its potential by way of example.

Temperature dependence of heavy ion-induced current transients in Si epilayer devices

We report on the temperature dependence of the heavy-ion transient-ion beam induced current response of Si epilayer devices from 80 to 300 K. The measurements were performed on a heavy-ion microbeam in conjunction with the new transient-ion beam induced current system developed at the Japan Atomic Energy Research Institute. Furthermore, we perform a detailed comparison with technology computer-aided design (TCAD) simulations and discuss the results in terms of TCAD modeling, experimental procedure, and the implications for temperature-related single-event upset modeling.

Dynamic Control of MOF‐5 Crystal Positioning Using a Magnetic Field

Paolo alcaro , * F rancois F Normandin , Masahide akahashi , T Paolo Scopece , Heinz Amenitsch , Stefano Costacurta , Cara M. Doherty , Jamie S. Laird , Matthew D. H. Layabio , F Lisi , Anita J. Hill , and Dario Buso *

High resolution imaging with high energy ion beams

Abstract The limits to high spatial resolution and the requirements for its achievement are discussed. A decade of evolution in high energy ion microscopy is reviewed, the principles, performances and possibilities of the many techniques are discussed. The resultant extreme demands placed upon the microprobe system are described. Finally, possibilities of, requirements for and progress towards nanometre resolution are reviewed.

High-injection carrier dynamics generated by MeV heavy ions impacting high-speed photodetectors

The generation of single event transients generated by the impact of high-energy ions in high-speed photodetectors leads to bit error rate degradation in optical communications in radiation hard environments such as space. High-energy heavy ions, in particular, generate a submicron electron-hole pair plasma with a picosecond temporal profile that results in ultrahigh-injection carrier dynamics which induce large space-charge effects. These space-charge effects disturb the local electric field, thereby determining the peak and duration of a single event transient. In this paper, we examine the transient response of Si p-i-n photodetectors irradiated with focused single MeV heavy ions for a range of ion energies chosen to ensure the same end of range but different average plasma densities. We discuss the role of high-injection effects on the evolving spatiotemporal response with the aid of three-dimensional technology computer-aided design software. The result of both measurement and simulation points to ch...

Ion Beam Induced Charge Collection (IBICC) microscopy of ICs: Relation to Single Event Upsets (SEU)

Abstract Single event upset (SEU) imaging is a new diagnostic technique recently developed using Sandias nuclear microprobe. This technique directly images, with micron resolution, those regions within an integrated circuit which are susceptible to ion-induced malfunctions. Such malfunctions are an increasing threat to space-based systems which make use of current-generation 1C designs. A complementary technique to SEU imaging involves measurement of the charge collection volumes within integrated circuits; charge collection is the underlying physical process responsible for single event phenomena. This technique, which we term ion beam induced charge collection (IBICC), has been used here and elsewhere to generate micron resolution maps of the charge collection response of integrated circuits. In this paper, we demonstrate the utility of combining the SEU imaging and IBICC techniques in order to gain a better understanding of single event upset phenomena. High resolution IBICC images are used to extract more detailed information from charge collection spectra than that obtained from conventional broad-area ion exposures, such as from radioactive sources. Lastly, we suggest the application of IBICC as a replacement for electron beam induced conduction/current (EBIC) measurements. As reductions in circuit feature size continue in the submicron regime, IBICC could certainly prove to be a technologically valuable replacement for EBIC and an important business opportunity for all nuclear microprobe facilities.

Distribution of Metals in the Termite Tumulitermes tumuli (Froggatt): Two Types of Malpighian Tubule Concretion Host Zn and Ca Mutually Exclusively

The aim of this study was to determine specific distribution of metals in the termite Tumulitermes tumuli (Froggatt) and identify specific organs within the termite that host elevated metals and therefore play an important role in the regulation and transfer of these back into the environment. Like other insects, termites bio-accumulate essential metals to reinforce cuticular structures and utilize storage detoxification for other metals including Ca, P, Mg and K. Previously, Mn and Zn have been found concentrated in mandible tips and are associated with increased hardness whereas Ca, P, Mg and K are accumulated in Malpighian tubules. Using high resolution Particle Induced X-Ray Emission (PIXE) mapping of whole termites and Scanning Electron Microscope (SEM) Energy Dispersive X-ray (EDX) spot analysis, localised accumulations of metals in the termite T. tumuli were identified. Tumulitermes tumuli was found to have proportionally high Mn concentrations in mandible tips. Malpighian tubules had significant enrichment of Zn (1.6%), Mg (4.9%), P (6.8%), Ca (2.7%) and K (2.4%). Synchrotron scanning X-ray Fluorescence Microprobe (XFM) mapping demonstrated two different concretion types defined by the mutually exclusive presence of Ca and Zn. In-situ SEM EDX realisation of these concretions is problematic due to the excitation volume caused by operating conditions required to detect minor amounts of Zn in the presence of significant amounts of Na. For this reason, previous researchers have not demonstrated this surprising finding.

Spectral response of a gamma and electron irradiated pin photodiode

The optical spectral response of Si pin photodiodes was examined after gamma and electron irradiation. We observed both a significant decrease in the peak optical response and peak position with increasing total dose. This effect was successfully explained by modeling the degradation of the minority carrier diffusion length in the base region. The diffusion length damage factor was estimated in the context of the nonionization energy loss (NIEL). A close agreement was found between the observed degradation behavior and that predicted by NIEL.

Ion-beam-induced charge-collection imaging of CMOS ICs

Charge collection regions of the Sandia TA670 16-Kbit SRAM have been directly imaged using a technique we call ion-beam-induced charge-collection (IBICC) imaging. During the IBICC measurement, the integrated circuit is connected through its power (VDD) or ground (VSS) pins to a charge sensitive preamp whose output is pulse-height analyzed while the IC is exposed to a scanned 0.1-μm resolution microbeam of heavy ions. The IC, in effect, functions as its own detector of the magnitude of charge collected following a heavy-ion strike. In this work, we examine the effect on IBICC imaging of varying power supply bias over a range of 0 to 15 V. Comparison of the IBICC image with the design layout for this integrated circuit unambiguously identifies source and drain regions of n-channel transistors and drain regions of p-channel transistors in the memory array. We were not able to image p-channel source regions in either the VDD or VSS configuration. This result is clearly explained on the basis of the IC design. Comparison of IBICC images with previously measured single-event-upset (SEU) images of the TA670 provide a more complete understanding of the mechanisms that govern single-event upset in this SRAM. IBICC holds great promise as a diagnostic tool to quantify the underlying charge collection processes that are responsible for single event upset in complex integrated circuits. It can also be applied to device failure analysis in a manner similar to EBIC, with potentially higher resolution.