graham hubler - Academia.edu (original) (raw)

Papers by graham hubler

MRS Bulletin, 1987

Ion beams are used extensively in materials research for processing and synthesis as well as for ... more Ion beams are used extensively in materials research for processing and synthesis as well as for characterization. In the last few years, enormous advances have been made regarding the use of ion beams for processing or synthesis, and this issue of the MRS BULLETIN will review some of those advances. (The use of ion beams for materials characterization will be the subject of a future issue of the BULLETIN.) The areas covered in this issue are ion implantation, ion beam mixing, ion-assisted deposition, and direct ion beam deposition. For each area, recognized experts in the field prepared overview articles that should be very interesting to those who are not active in the field, and that should be useful to other experts in the field.The first large-scale use of ion beams for materials modification took place in the semiconductor industry more than 20 years ago when ion implantation began to be used to dope the near-surface region of silicon with Group III or Group V dopants. The use...

La presente invention porte, de maniere generale, sur un procede de detection de substance chimiq... more La presente invention porte, de maniere generale, sur un procede de detection de substance chimique sans contact ou a distance par excitation selective d'un ou de plusieurs analytes d'interet a l'aide d'une source infrarouge (IR) reglee sur au moins une bande d'absorption specifique, sans decomposer de maniere significative l'analyte et de determination du point de savoir si l'analyte est present par comparaison des photons emis avec un signal de detecteur IR fait avant et pendant ou peu apres avoir excite l'analyte. Un autre mode de realisation de la presente invention porte sur un procede de detection de substance chimique sans contact ou a distance par excitation selective d'un ou de plusieurs analytes d'interet a l'aide d'une source IR reglee sur au moins une bande d'absorption specifique, sans decomposer de maniere significative l'analyte, l'analyte etant suffisamment excite pour generer un nuage de vapeur, le nuage et...

Annual Meeting Optical Society of America

The synthesis of high quality gallium arsenide–aluminum arsenide (GaAs–AlAs) superlattices has in... more The synthesis of high quality gallium arsenide–aluminum arsenide (GaAs–AlAs) superlattices has initiated a new class of optical materials with important consequences in the area of optoelectronics. For many applications it will be necessary to accurately characterize the optical properties of these materials in frequency regions of interest. In the present investigation, infrared reflectance spectroscopy is used to determine the optical indices of several GaAs–AlAs superlattice films in the near-infrared region (4000–10,000 cm−1). Each of the superlattices under study had an average aluminum mole fraction equal to 0.523. The reflectivity measurements indicate that the optical index of a particular superlattice can be higher or lower than that of the equivalent AlGaAs alloy depending on the layer periodicity of the superlattice. These results are compared with theoretical treatments of GaAs–AlAs superlattices1 and with prior experimental studies at energies above 1.2 eV.2

MRS Proceedings, 1983

ABSTRACTCharacterization of the two metastable states of amorphous Si produced by ion implantatio... more ABSTRACTCharacterization of the two metastable states of amorphous Si produced by ion implantation is extended to include electron paramagnetic resonance, fundamental absorption edge, and density measurements in addition to infrared reflection. It is found that the properties of the two a-Si states are not dependent upon the mass of the incident ion (12C, 29Si, 31p, 120Sn) or upon the anneal temperature for 400°≤TA≤600°C. The dangling-bond density drops about a factor of 2, the absorption coefficient drops by more than a factor of 5, but the density does not change when the a-Si makes a transition between the two states.

Nuclear Instruments and Methods in Physics Research, 1981

Ion implantation is being Investigated as a technique tor the benehclal modtficatlon ol surface s... more Ion implantation is being Investigated as a technique tor the benehclal modtficatlon ol surface sensitive, llte-hmitlng properties o) metals, mdudmg resistance to corroston, wear, and fatigue Ion implantation can produce a graded alloy from the surface to the unchanged underlymg bulk alloy so that both the surface alloy and bulk alloy can be Independently opttmlzed, and the technique promises the ability to produce umque metastable surface alloys With typical implantatmn energies m the range of 10-200 keV, tmptantatmn depths are less a fe;~ hundred nanometers These implantation depths are well suited for study by means of 1on beam analysis techmques Thts paper reviews examples ot mechamcal and corrosion property changes reduced by ion Implantation and describes m each case how ton beam surface layer analysis provided mformatlon useful to the present understanding of the cttects observed

AIP Conference Proceedings, 1999

ABSTRACT A new LabVIEW-based control system for the existing tandem accelerator and new AMS compo... more ABSTRACT A new LabVIEW-based control system for the existing tandem accelerator and new AMS components has been implemented at the Trace Element Accelerator Mass Spectrometry (TEAMS) facility at the Naval Research Laboratory. Through the use of Device Interfaces (DIs) distributed along a fiber optic network, virtually every component of the accelerator system can be controlled from any networked computer terminal as well as remotely via modem or the internet. This paper discusses the LabVIEW-based control software, including remote operation, automatic calculation of ion optical component parameters, beam optimization, and data logging and retrieval.

Abstract : A copper mirror and method of treating copper reflective surfaces so they may be used ... more Abstract : A copper mirror and method of treating copper reflective surfaces so they may be used in a laser system. A copper mirror is placed in a vacuum chamber and ions are implanted into the surface to produce a good reflective surface which will not tarnish or be damaged by high-power lasers. (Author)

SPIE Proceedings, 1986

ABSTRACT

Nuclear Instruments and Methods, 1978

Abstract Profiles of ion-implanted Be concentrations in GaAs substrates were measured by means of... more Abstract Profiles of ion-implanted Be concentrations in GaAs substrates were measured by means of the 9 Be(p, α ) 6 Li reaction and SIMS methods. A magnetic spectrometer was used to detect the α-particles in a 45° scattering geometry. Profiles obtained from the two methods were in substantial agreement.

Thin films of substoichiometric silicon nitride were grown by the use of ion beam assisted deposi... more Thin films of substoichiometric silicon nitride were grown by the use of ion beam assisted deposition. The amorphous films were annealed at high temperatures (1017 to 1200C) to produce crystalline alpha-Si3N4. Both highly symmetric spherulitic crystal morphologies and irregular fractal aggregates were seen. In the latter case, a fractal dimension of 1.2 was measured. These two macroscopically different forms possessed

Advanced Applications of Ion Implantation, 1985

Recent work has demonstrated that the infrared properties (refractive index and absorption) of am... more Recent work has demonstrated that the infrared properties (refractive index and absorption) of amorphous silicon and germanium prepared by ion implantation depend upon the low temperature thermal annealing history (1500C<T<6000C). This thermal relaxation phenomenon is the subject of this review. The data suggest the change in refractive index is caused by a structural reorganization of a continuous random network but that changes in absorption and spin density are chiefly caused by the annealing of defects within the amorphous structure.

Surface and Coatings Technology, 1992

Abstract The pitting potential of silicon nitride ion beam assisted deposited (IBAD) coatings on ... more Abstract The pitting potential of silicon nitride ion beam assisted deposited (IBAD) coatings on aluminum in deaerated 0.1 M NaCl solutions increased with coating thickness for coatings ranging from 0.01 to 2.0 μm. Rutherford backscattering spectroscopy and optical techniques showed the films to be nearly stoichiometric Si 3 N 4 . X-ray photoelectron spectroscopy showed that the surface of the IBAD samples is composed of Si 3 N 4 , SiO 2 , and a silicon oxynitride species. Pit propagation beneath the coatings proceeds by blister formation and rupture.

Fourth International Symposium on Laser Precision Microfabrication, 2003

As laser micromachining is applied to ever smaller structures and more complex materials, the dem... more As laser micromachining is applied to ever smaller structures and more complex materials, the demand for greater control of the laser energy budget, in space and time, grows commensurately. Here we describe materials modification using picosecond resonant laser excitation in the mid-infrared spectral region to create spatially and temporally dense vibrational, rather than electronic, excitation. Examples include ablation of fused