Characterization of Zirconium - Diamond Interfaces

1996 ◽  
Vol 423 ◽  
Author(s):  
P. K. Baumann ◽  
S. P. Bozeman ◽  
B. L. Ward ◽  
R. J. Nemanich
Keyword(s):  
Electron Affinity ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Threshold Field ◽  
Diamond Surfaces ◽  
Field Emission Current ◽  
Current Voltage ◽  
Single Crystal Diamond ◽  
A Current

AbstractThin Zr films were deposited on natural single crystal diamond (100) substrates by ebeam evaporation in ultra-high vacuum (UHV). Before metal deposition the surfaces were cleaned by UHV anneals at either 500°C or 1150°C. Following either one of these treatments a positive electron affinity was determined by means of UV photoemission spectroscopy (UPS). Depositing 2Å of Zr induced a NEA on both surfaces. Field emission current - voltage measurements resulted in a threshold field (for a current of 0.1 µA) of 79 V/µm for positive electron affinity diamond surfaces and values as low as 20 V/µm for Zr on diamond.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

Majority Carrier Transport Across Semiconductor Grain Boundaries

1990 ◽  
Vol 209 ◽  
Author(s):  
S.F. Nelson ◽  
P.V. Evans ◽  
S.L. Sass ◽  
D.A. Smith
Keyword(s):  
Carrier Transport ◽  
High Vacuum ◽  
Thermionic Emission ◽  
Ultra High Vacuum ◽  
Defect States ◽  
Intrinsic Structure ◽  
Majority Carrier ◽  
Float Zone ◽  
Current Voltage ◽  
Misorientation Angles

AbstractMajority carrier transport measurements were made across the potential barriers at (100) twist boundaries in silicon. The bicrystals were prepared by hot-pressing single crystals of lightly doped float-zone material, under ultra-high vacuum conditions. The current - voltage measurements were analyzed using combined drift-diffusion and thermionic emission transport mechanisms, and incorporating some inhomogeneity in the charge distribution at the boundary. Evidence has been found for a small, Nd = 3 × 1010 cm−2, density of mono-energetic defect states near midgap, in bicrystals characterized by a variety of misorientation angles. This density is too small to result from the intrinsic structure of the boundary. In addition, no dependence was found on misorientation angle.

Growth and Characterization of High Quality Si 1- x-y Ge x C y Alloy Grown by Ultra-High Vacuum Chemical Vapor Deposition

1999 ◽  
Vol 16 (10) ◽  
pp. 750-752 ◽  
Author(s):  
Zhen Qi ◽  
Jing-yun Huang ◽  
Zhi-zhen Ye ◽  
Huan-ming Lu ◽  
Wei-hua Chen ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
High Quality

Investigation of Epitaxial Overgrowth on Germanium Quantum Dots

2001 ◽  
Vol 676 ◽  
Author(s):  
David W. Greve ◽  
Qian Zhao
Keyword(s):  
Quantum Dots ◽  
Vapor Deposition ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Ultra High Vacuum ◽  
Reciprocal Space Mapping ◽  
Silicon Epitaxial Layer ◽  
Germanium Quantum Dots ◽  
Uniform Quantum

ABSTRACTWe report on the characterization of germanium quantum dots grown on silicon (001) substrates by ultra-high vacuum chemical vapor deposition (UHV/CVD). In many applications small and uniform quantum dots are required which must be overgrown by a silicon epitaxial layer. We report here on the effect of carbon predeposition from methylsilane on the dot size and uniformity. In addition, we use reciprocal space mapping to evaluate the qualityof epitaxial layers which overgrow the quantum dots. The results show some differences from previous reports on MBE-grown dots.

Characterization of Si pn junctions fabricated by direct wafer bonding in ultra-high vacuum

1998 ◽  
Vol 72 (9) ◽  
pp. 1095-1097 ◽  
Author(s):  
K. D. Hobart ◽  
M. E. Twigg ◽  
F. J. Kub ◽  
C. A. Desmond
Keyword(s):  
Wafer Bonding ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Direct Wafer Bonding ◽  
Pn Junctions

Preparation and spectroscopic characterization of a thin polymer film in ultra high vacuum: 2,5‐distyrylpyrazine

1991 ◽  
Vol 94 (4) ◽  
pp. 3235-3241 ◽  
Author(s):  
M. Abraham ◽  
J. Dütting ◽  
M. Schreck ◽  
R. Lege ◽  
S. Reich ◽  
...  
Keyword(s):  
Polymer Film ◽  
High Vacuum ◽  
Spectroscopic Characterization ◽  
Ultra High Vacuum ◽  
Thin Polymer Film ◽  
Thin Polymer

Gas-Tight Oxides - Reality or Just a Hope

2006 ◽  
Vol 522-523 ◽  
pp. 93-102 ◽  
Author(s):  
C. Anghel ◽  
Gunnar Hultquist ◽  
Qian Dong ◽  
J. Rundgren ◽  
Isao Saeki ◽  
...  
Keyword(s):  
Mathematical Model ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Gas Content ◽  
Molar Ratio ◽  
Protection Measure ◽  
Straightforward Method ◽  
Gas Tight ◽  
The Mathematical Model

A better understanding of the transport properties of gases in oxides is certainly very important in many applications. In the case of metals, a general protection measure against corrosion implies formation of a dense metal oxide scale. The scale should act as a barrier against gas transport and consequently it needs to be gas-tight. This is often assumed but rarely, if ever, confirmed. Hence there is a need for characterization of micro- and/or meso- pores formed especially during the early oxidation stage of metallic materials. This paper presents a novel and relatively straightforward method for characterization of gas release from an oxide previously equilibrated in a controlled atmosphere. The geometry of the sample is approximated to be a plate. The plate can be self-supporting or constitute a scale on a substrate. A mathematical model for calculation of diffusivity and gas content is given for this geometry. A desorption experiment, involving a mass spectrometer placed in ultra high vacuum, can be used to determine diffusivity and amount of gas released with aid of the mathematical model. The method is validated in measurements of diffusivity and solubility of He in quartz and applied in characterization of two Zroxides and one Fe oxide. From the outgassed amounts of water and nitrogen the H2O/N2 molar ratio can be used to estimate an effective pore size in oxides.

Electronics Application for Fullerenes

1994 ◽  
Vol 349 ◽  
Author(s):  
R.L. McNally ◽  
F R. Brotzen ◽  
A.J. Griffin ◽  
P.J. Loos ◽  
E.V. Barrera
Keyword(s):  
Thin Film ◽  
Applied Voltage ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Concentration Profiles ◽  
Wavelength Dispersive Spectroscopy ◽  
Sem Micrographs ◽  
Noticeable Change ◽  
Metal Semiconductor Metal ◽  
Current Voltage

ABSTRACTThin-film Al-C60-Al trilayered structures were sublimated under ultra high vacuum (UHV) conditions for the purpose of investigating their current-voltage (I-V) properties. These metal-semiconductor-metal devices exhibited rapid and irreversible drop in resistance of about two orders of magnitude under an applied voltage of 0.67 to 0.75V. Approximate initial and final resistances were 1050 Ω and 8 Ω respectively. Wavelength Dispersive Spectroscopy (WDS) indicated no noticeable change in phase of the fullerene inter-layer after the irreversible drop in resistance. These results, SEM micrographs and concentration profiles were concordant with diffusion of top layer Al through the fullerene layer as the most likely cause of the change in resistance.

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