Photoelectron Emission from the Cesiated Diamond (110) Surface

1995 ◽  
Vol 416 ◽  
Author(s):  
C. A. Fox ◽  
M. A. Kelly ◽  
S. B. Hagstrom ◽  
R. Cao ◽  
G. Vergara ◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Secondary Electron ◽  
Diamond Surface ◽  
Photoemission Spectroscopy ◽  
Negative Electron Affinity ◽  
Photoelectron Emission ◽  
Band Bending ◽  
X Ray ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron

ABSTRACTCesiation of type IIB diamond (110) crystals was studied using a combination of ultraviolet photoemission spectroscopy, x-ray photoemission spectroscopy, and low energy electron diffraction. The diamond (110) crystal was hydrogen treated by exposure to a hydrogen microwave discharge. Although cesium was largely unreactive with the hydrogenated diamond surface, cesiation yielded a large enhancement in the secondary electron yield of the diamond surface and the negative electron affinity (NEA) condition. An increase in the downwards band bending of approximately 0.75-0.9 eV was inferred from the shift in the valence band edge following cesiation. In addition, (lx 1) LEED patterns were observed at all cesium coverages. Exposure of the cesiated diamond surface to molecular oxygen significantly reduced the NEA peak (relative to the secondary electron background); however, recovery of the NEA peak was observed when the molecular oxygen source was removed.

Fluorine Atom Addition to the Diamond (111) Surface

1992 ◽  
Vol 242 ◽  
Author(s):  
Andrew Freedman ◽  
Gary N. Robinson ◽  
Charter D. Stinespring
Keyword(s):  
Electron Diffraction ◽  
Photoelectron Spectroscopy ◽  
Fluorine Atom ◽  
Low Energy ◽  
Diamond Surface ◽  
X Ray ◽  
Low Energy Electron Diffraction ◽  
Atomic Fluorine ◽  
Low Energy Electron ◽  
Diffraction Patterns

ABSTRACTDiamond (111) surfaces with the dehydrogenerated 2×1 reconstruction have been exposed to a beam of atomic fluorine at 300 K. The uptake of fluorine, as measured using X-ray photoelectron spectroscopy, is quite efficient and saturates at a coverage of less than a monolayer. Low energy electron diffraction patterns indicate that fluorine termination of the diamond surface produces a lxi bulk-like reconstruction in contrast to the disordered surface produced on the (100) surface.

Removal of Fluorine From a Si (100) Surface by a Remote RF Hydrogen Plasma

1995 ◽  
Vol 386 ◽  
Author(s):  
J. P. Barnak ◽  
S. King ◽  
J. Montgomery ◽  
Ja-Hum Ku ◽  
R. J. Nemanich
Keyword(s):  
Atomic Hydrogen ◽  
Hydrogen Plasma ◽  
Photoemission Spectroscopy ◽  
Fluorine Concentration ◽  
Plasma Exposure ◽  
Xps Spectra ◽  
X Ray ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Vacuum Anneal

ABSTRACTFluorine contamination was removed from a Si(100) surface by an atomic H flux. The surface was intentionally contaminated to approximate the residual fluorine concentration remaining after a concentrated HF last process. By dipping the wafers in concentrated HF the thin oxide was removed and replaced with a hydrogen and fluorine terminated surface. This surface was then either vacuum annealed or exposed to a 20 Watt rf excited H-plasma at 50 mTorr, in order to achieve an atomically clean surface. The substrate temperature during the Hplasma exposure and vacuum anneal was 450°C. The surface chemistry was characterized with x-ray photoemission spectroscopy (XPS), auger electron spectroscopy (AES), and angle-resolved UV photoemission spectroscopy (ARUPS). The surface symmetry was characterized with low energy electron diffraction (LEED). Before the H-plasma exposure, the XPS spectra indicated Si-F bonding, and a l×1 LEED diffraction pattern was observed. Immediately following the Hplasma exposure, the fluorine concentration was reduced below detection limits of XPS, and the surface showed a 2×1 reconstruction. A mechanism is proposed by which molecular HF results from atomic hydrogen interactions with fluorine on the surface.

Atomic Structure of Non-Basal-Plane SiC Surfaces: Hydrogen Etching and Surface Phase Transformations

2006 ◽  
Vol 911 ◽  
Author(s):  
Serguei Soubatch ◽  
Wai Y. Lee ◽  
Martin Hetzel ◽  
Chariya Virojanadara ◽  
Camilla Coletti ◽  
...  
Keyword(s):  
Photoemission Spectroscopy ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Hydrogen Etching ◽  
X Ray ◽  
Force Microscopy ◽  
Low Energy Electron Diffraction ◽  
Atomic Force ◽  
Surface Phases ◽  
Low Energy Electron

AbstractA-plane (11-20) and diagonal cut (1-102) and (-110-2) surfaces of 4H-SiC have been investigated using atomic force microscopy (AFM), low-energy electron diffraction (LEED), Auger electron spectroscopy (AES), X-ray photoemission spectroscopy (XPS) and scanning tunneling microscopy (STM). After hydrogen etching the surfaces show large, flat terraces. On SiC(11-20) steps down to single atomic heights are observed. On the diagonal cut surfaces steps run parallel and perpendicular to the [-1101] direction, yet drastically different morphologies for the two isomorphic orientations are found. All surfaces immediately display a sharp LEED pattern. For SiC(1-102) and SiC(-110-2) the additional significant presence of oxygen in the AES spectra indicates the development of an ordered oxide. All three surfaces show an oxygen free, well ordered surface after Si deposition and annealing. A transformation between different surface phases is observed upon annealing.

Pyrite surface environment drives molecular adsorption: cystine on pyrite(100) investigated by X-ray photoemission spectroscopy and low energy electron diffraction

2016 ◽  
Vol 18 (39) ◽  
pp. 27219-27225 ◽  
Author(s):  
M. Sanchez-Arenillas ◽  
E. Mateo-Marti
Keyword(s):  
Critical Parameter ◽  
Annealing Process ◽  
Low Energy ◽  
Photoemission Spectroscopy ◽  
Pyrite Surface ◽  
X Ray ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron ◽  
Pre Treatment ◽  
Surface Environment

The annealing process for pre-treatment of pyrite surfaces is a critical parameter in promoting ordering on the surface and it has chemical implications on the cystine adsorbed molecules.

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