Examination of the Silicon – Silicon Carbide Interface by Ultraviolet Photoemission Spectroscopy

1998 ◽  
Vol 512 ◽  
Author(s):  
C. Koitzscht ◽  
M. O'Brient ◽  
D. Johri ◽  
A. Stoltzt ◽  
R. Nemanicht
Keyword(s):  
Silicon Carbide ◽  
Valence Band ◽  
High Vacuum ◽  
Valence Band Maximum ◽  
Integrated System ◽  
Ultra High Vacuum ◽  
Photoemission Spectroscopy ◽  
Ambient Atmosphere ◽  
Silicon Silicon ◽  
State Feature

ABSTRACTPhotoemission spectroscopy (UPS) was used to investigate the interface properties of deposited silicon on hexagonal 6H-silicon carbide. SiC cleaned in Si flux from a molecular beam epitaxy (MBE) system was used for this study. All processes were accomplished in an ultra high vacuum integrated system that allowed all cleaning, deposition, and analysis to be completed without exposure to ambient atmosphere. Thicknesses of sub- to multiple monolayers were deposited and the valence band structure was investigated. The valence band maximum (VBM) was observed to shift for Si depositions greater than 1 monolayer. The VBM offset was determined to be 2.4eV for a layer of 60Å Si on SiC. Furthermore, the prominent surface state feature of the silicon carbide (0001)si surface is reduced after Si deposition. The results are discussed in terms of the electronic properties of the Si – SiC interface.

Photoemission Study of The Electronic Structure of Wurtzite Gan(0001) Surfaces

1997 ◽  
Vol 482 ◽  
Author(s):  
Kevin E. Smith ◽  
Sarnjeet S. Dhesi ◽  
Cristian B. Stagarescu ◽  
James Downes ◽  
D. Doppalapudi ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Surface State ◽  
High Vacuum ◽  
Valence Band Maximum ◽  
Ultra High Vacuum ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Surface Electronic Structure ◽  
Bond State ◽  
Photoemission Study

AbstractThe surface electronic structure of wurtzite GaN (0001) (1 × 1) has been investigated using angle-resolved photoemission spectroscopy. Surfaces were cleaned by repeated cycles of N2 ion bombardment and annealing in ultra-high vacuum. A well-defined surface state below the top of the valence band is clearly observed. This state is sensitive to the adsorption of both activated H2 and O2, and exists in a projected bulk band gap, below the valence band maximum. The state shows no dispersion perpendicular or parallel to the surface. The symmetry of this surface state is even with respect to the mirror planes of the surface and polarization measurements indicate that it is of spz character, consistent with a dangling bond state.

Investigation of Thin Pd-Ge Layer Formation Using Synchrotron Vacuum Ultraviolet Photoemission Spectroscopy

1990 ◽  
Vol 181 ◽  
Author(s):  
P. L. Meissner ◽  
J. C. Bravman ◽  
T. Kendelewicz ◽  
K. Miyano ◽  
W. E. Spicer ◽  
...  
Keyword(s):  
Room Temperature ◽  
Vacuum Ultraviolet ◽  
Diffusion Mechanism ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Photoemission Spectroscopy ◽  
Layer Formation ◽  
Primary Reaction ◽  
Ultraviolet Photoemission Spectroscopy

ABSTRACTThe formation of Pd-Ge layers was studied as a function of deposition and annealing using synchrotron Ultraviolet Photoemission Spectroscopy (UPS). Pd depositions ranging in thickness from 0.5 monolayers (ML) to 44 ML were examined in-situ on Ge (111) cleaved in ultra-high vacuum. The primary reaction components appear to be Pd2Ge and PdGe. Comparison of bulk and surface sensitive Ge 3d core levels for even the highest coverages indicates that Ge segregates to the surface at room temperature. Such low temperature segregation suggests that Ge can diffuse via a rapid diffusion mechanism.

Modeling of Charge Transport in a Hybrid Metal / Organic / Inorganic Device

2007 ◽  
Vol 1029 ◽  
Author(s):  
Henry Alberto Mendez
Keyword(s):  
High Vacuum ◽  
Ultra High Vacuum ◽  
Photoemission Spectroscopy ◽  
Organic Thin Film ◽  
Electrical Measurements ◽  
Semiconductor Heterostructure ◽  
Metal Organic ◽  
Inorganic Semiconductor ◽  
Analytical Expressions

AbstractA Metal / Organic / Inorganic semiconductor heterostructure was built and characterized in situ under ultra-high vacuum conditions (UHV). The aim was to investigate the influence of a perylene-derivative organic thin film on the transport electronic properties of Schottky Ag / GaAs diodes. The device was studied using a combination of photoemission spectroscopy (PES) and electrical measurements. The obtained results were discussed using the analytical expressions of a trapped charge limited current (TCLC) model.

Surface Chemical Analysis of Nanoparticles for Commercial Products and Devices

2013 ◽  
Vol 1533 ◽  
Author(s):  
Marie-Isabelle Baraton
Keyword(s):  
Chemical Composition ◽  
Surface Chemistry ◽  
Surface Analysis ◽  
Surface Composition ◽  
High Vacuum ◽  
Surface Reactivity ◽  
Ultra High Vacuum ◽  
Ambient Atmosphere ◽  
Surface Chemical ◽  
Surface Chemical Composition

ABSTRACTAmongst the list of the measurands specific to nanoparticles, size and shape definitely matter but surface chemistry is also often cited. While it is now largely recognized that surface composition, structure and reactivity are perhaps the dominant parameters controlling properties of nanoparticles, surface chemistry is one of the key characteristics of nanoparticles which is seldom or inappropriately evaluated, as it has been identified by international organizations (such as ISO, BIPM or CEN). The usual techniques for surface analysis of materials often require ultra-high vacuum (UHV) conditions and are hardly applicable to nanoparticles. Moreover, because the surface chemical composition and reactivity are dependent on the environmental conditions, the results obtained under UHV cannot be extrapolated to nanoparticles in ambient atmosphere or dispersed in liquids.After an analysis of the stakes and challenges in the surface characterization of nanoparticles and a very brief overview of the usual techniques for surface studies, this paper presents the performance of Fourier transform infrared (FTIR) spectroscopy to investigate surface chemical composition, surface reactivity and surface functionalization of nanoparticles. As illustrating examples, the results of the FTIR surface analysis of different kinds of ceramic nanoparticles are discussed with regard to several fields of applications.

Photoemission Study of the α-Sn/Cdte(110) Interface Growth

1987 ◽  
Vol 94 ◽  
Author(s):  
Ming Tang ◽  
David W. Niles ◽  
Isaac Hernández-Calderón ◽  
Hartmut Hóchst
Keyword(s):  
Synchrotron Radiation ◽  
Fermi Level ◽  
Valence Band ◽  
Valence Band Maximum ◽  
Photoemission Spectroscopy ◽  
Mbe Growth ◽  
Band Maximum ◽  
Interface Growth ◽  
Interfacial Growth ◽  
Photoemission Study

ABSTRACTAngular Resolved Photoemission Spectroscopy with Synchrotron radiation has been used to study the MBE growth of α-Sn on CdTe(110). Sn grows epitaxially and the Fermi level pins at 0.72eV above the CdTe valence band maximum. Outdiffusion or segregation of Cd in the α-Sn layer is not observed. For small Sn coverages the Sn4d core spectra show a second component which may be due to the initial interfacial growth of SnTe.

Nanometre multi-axis manipulator with interferometer control

2011 ◽  
Vol 1 (MEDSI-6) ◽  
Author(s):  
J.-L. Giorgetta ◽  
M.-C. Asensio ◽  
J. Avila
Keyword(s):  
Thermal Effects ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Photoemission Spectroscopy ◽  
Mechanical Vibrations ◽  
X Ray ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Microscope Technique ◽  
X Ray Absorption ◽  
Non Destructive

As one of the latest beamlines at the Synchrotron Radiation SOLEIL facility, ANTARES beamline will offer an X-ray nanoprobe able to combine four powerful non-destructive techniques: (i) angle-resolved photoemission spectroscopy, (ii) core-level photoemission (X-ray photo electron spectroscopy), (iii) X-ray absorption spectroscopy and (iv) X-ray fluorescence. ANTARES microscope has implemented a powerful and innovative nano-scanning photoemission microscope technique using three independent detectors in combination with a 14 integrated-axes manipulator. Microscope motion requirements involve linear and rotary positioning based on non-magnetic ceramic servo motors, compatible with ultra-high-vacuum conditions. A complete four-head interferometer system monitors continuously, with nano-metric precision, the alignment of the sample and focalization optics during the scanning operation. An accurate electronic feedback avoids image distortion due to mechanical vibrations or thermal effects.

scholarly journals Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

2015 ◽  
Vol 6 ◽  
pp. 2485-2497 ◽  
Author(s):  
Urs Gysin ◽  
Thilo Glatzel ◽  
Thomas Schmölzer ◽  
Adolf Schöner ◽  
Sergey Reshanov ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Electrostatic Force ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Probe ◽  
Electrostatic Force Microscopy ◽  
Kelvin Probe ◽  
Large Area ◽  
Force Microscopy ◽  
Probe Microscope

Background: The resolution in electrostatic force microscopy (EFM), a descendant of atomic force microscopy (AFM), has reached nanometre dimensions, necessary to investigate integrated circuits in modern electronic devices. However, the characterization of conducting or semiconducting power devices with EFM methods requires an accurate and reliable technique from the nanometre up to the micrometre scale. For high force sensitivity it is indispensable to operate the microscope under high to ultra-high vacuum (UHV) conditions to suppress viscous damping of the sensor. Furthermore, UHV environment allows for the analysis of clean surfaces under controlled environmental conditions. Because of these requirements we built a large area scanning probe microscope operating under UHV conditions at room temperature allowing to perform various electrical measurements, such as Kelvin probe force microscopy, scanning capacitance force microscopy, scanning spreading resistance microscopy, and also electrostatic force microscopy at higher harmonics. The instrument incorporates beside a standard beam deflection detection system a closed loop scanner with a scan range of 100 μm in lateral and 25 μm in vertical direction as well as an additional fibre optics. This enables the illumination of the tip–sample interface for optically excited measurements such as local surface photo voltage detection. Results: We present Kelvin probe force microscopy (KPFM) measurements before and after sputtering of a copper alloy with chromium grains used as electrical contact surface in ultra-high power switches. In addition, we discuss KPFM measurements on cross sections of cleaved silicon carbide structures: a calibration layer sample and a power rectifier. To demonstrate the benefit of surface photo voltage measurements, we analysed the contact potential difference of a silicon carbide p/n-junction under illumination.

Heating, Laser Irradiation and Passivation Study on the Light-Emitting Porous Silicon

1991 ◽  
Vol 256 ◽  
Author(s):  
H. C. Chen ◽  
W. Wang ◽  
K. N. Manjularani ◽  
L. C. Snyder ◽  
X. L. Zheng
Keyword(s):  
Laser Irradiation ◽  
Light Emission ◽  
High Vacuum ◽  
Laser Wavelength ◽  
Ultra High Vacuum ◽  
Ambient Atmosphere ◽  
Severe Problem ◽  
Light Emitting ◽  
Ecr Plasma ◽  
Plasma Passivation

ABSTRACTFor light-emitting porous Si there has been a severe problem with instability and degradation of the light emission. We report that a stabilization of the emission intensity and the peak energy can be achieved in air by a proper laser irradiation, In-situ photoluminescence measurements were performed to monitor the degradation and stabilization process under different conditions and parameters, such as laser power, laser wavelength and environment (ambient atmosphere of certain gas or ultra high vacuum). We found oxygen is the major cause for the emission degradation in this laser enhanced adsorption process, and the laser heating effect can be excluded. For a comparison we study the reversible thermal heating and quenching process. We also discuss microwave and ECR plasma passivation results.

Thin Pyrolytic Graphite Films for Electron Microscope Substrates

1971 ◽  
Vol 29 ◽  
pp. 226-227 ◽  
Author(s):  
George H. N. Riddle ◽  
Benjamin M. Siegel
Keyword(s):  
Vacuum Chamber ◽  
Pyrolytic Graphite ◽  
High Vacuum ◽  
Dark Field ◽  
Ultra High Vacuum ◽  
Graphite Substrate ◽  
Nickel Substrate ◽  
Routine Procedure ◽  
Field Electron Microscopy ◽  
Dark Field Electron

A routine procedure for growing very thin graphite substrate films has been developed. The films are grown pyrolytically in an ultra-high vacuum chamber by exposing (111) epitaxial nickel films to carbon monoxide gas. The nickel serves as a catalyst for the disproportionation of CO through the reaction 2C0 → C + CO2. The nickel catalyst is prepared by evaporation onto artificial mica at 400°C and annealing for 1/2 hour at 600°C in vacuum. Exposure of the annealed nickel to 1 torr CO for 3 hours at 500°C results in the growth of very thin continuous graphite films. The graphite is stripped from its nickel substrate in acid and mounted on holey formvar support films for use as specimen substrates.The graphite films, self-supporting over formvar holes up to five microns in diameter, have been studied by bright and dark field electron microscopy, by electron diffraction, and have been shadowed to reveal their topography and thickness. The films consist of individual crystallites typically a micron across with their basal planes parallel to the surface but oriented in different, apparently random directions about the normal to the basal plane.

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