Direct observation of the work function evolution of graphene-two-dimensional metal contacts

2014 ◽  
Vol 2 (38) ◽  
pp. 8042-8046 ◽  
Author(s):  
Songbo Yang ◽  
Peng Zhou ◽  
Lin Chen ◽  
Qingqing Sun ◽  
Pengfei Wang ◽  
...  
Keyword(s):  
Work Function ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
Graphene Monolayer ◽  
Two Dimensional ◽  
Metal Contacts ◽  
System P

The work function evolution of a graphene monolayer under two-dimensional metal electrodes was studied by combining in situ metal deposition and ultraviolet photoelectron spectroscopy under an ultra-high vacuum system.

Ultra-high vacuum chemical vapor deposition and in situ characterization of titanium oxide thin films

1991 ◽  
Vol 6 (9) ◽  
pp. 1913-1918 ◽  
Author(s):  
Jiong-Ping Lu ◽  
Rishi Raj
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Titanium Oxide ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Titanium Isopropoxide ◽  
Ultra High Vacuum

Chemical vapor deposition (CVD) of titanium oxide films has been performed for the first time under ultra-high vacuum (UHV) conditions. The films were deposited through the pyrolysis reaction of titanium isopropoxide, Ti(OPri)4, and in situ characterized by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). A small amount of C incorporation was observed during the initial stages of deposition, through the interaction of precursor molecules with the bare Si substrate. Subsequent deposition produces pure and stoichiometric TiO2 films. Si–O bond formation was detected in the film-substrate interface. Deposition rate was found to increase with the substrate temperature. Ultra-high vacuum chemical vapor deposition (UHV-CVD) is especially useful to study the initial stages of the CVD processes, to prepare ultra-thin films, and to investigate the composition of deposited films without the interference from ambient impurities.

Characteristics and Recovery of SI Surfaces Plasma Etching in CHF3 / C2F6

1992 ◽  
Vol 259 ◽  
Author(s):  
H.-H. Park ◽  
K.-H. Kwon ◽  
B.-H. Koak ◽  
S.-M. Lee ◽  
O.-J. Kwon ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Silicon Surface ◽  
Secondary Ion Mass Spectrometry ◽  
High Vacuum ◽  
Silicon Layer ◽  
Ultra High Vacuum ◽  
Rapid Thermal Anneal ◽  
Condition C ◽  
Secondary Ion

ABSTRACTThe effects of SiO2 reactive ion etching (RIE) in CHF3 / C2F6 on the surface properties of the underlying Si substrate have been studied by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) techniques. The observed two major modifications are (i) a ∼50nm thick silicon layer which contains carbon and fluorine and (ii) 2∼3nm thick residue layer composed entirely of carbon, fluorine, oxygen and hydrogen on the silicon surface. The thermal behaviors of attributed peaks for C 1s, Si 2p, O 1s and F 1s of residue film have been analyzed after in-situ resistive anneal under ultra high vacuum (UHV) condition. C-F1, C-F2 and C-F3 bonds decompose and form C-CFx (x≤3) bonds above 200°C. Above 400°C, C-CFx bonds also decompose to C-C/H bonds. For recovery of the modified silicon surface, reactive ion etched specimens have been exposed to an oxygen plasma. By XPS analysis, the effect of an O2 plasma treatment has been revealed to be completed within 20min. With an O2 plasma pre-treated, a rapid thermal anneal (RTA) treatment as low as 500°2 is found to be effective for removal of impurities in the silicon.

Temperature Induced Phase Transformation on the 4H-SiC(11-20) Surface

2006 ◽  
Vol 527-529 ◽  
pp. 673-676 ◽  
Author(s):  
W.Y. Lee ◽  
S. Soubatch ◽  
Ulrich Starke
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
X Ray ◽  
Force Microscopy ◽  
Low Energy Electron Diffraction ◽  
Atomic Force ◽  
Surface Phases ◽  
Low Energy Electron

The atomic structure of the 4H-SiC(11 2 0) surface including possible phase transformations via Si deposition and annealing has been investigated using low energy electron diffraction (LEED), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The sample is initially prepared by hydrogen etching before loading into the ultra-high vacuum system. The sample is then out-gassed to remove oxygen from the surface. To explore the existence of ordered surface phases, Si is deposited on the sample at 850°C for 15 minutes followed by a series of sequential annealing steps. Throughout this process, the surface is monitored by LEED, AES and XPS. LEED shows that the surface continuously maintains a (1×1) periodicity. Yet, two unique and distinguishable (1×1) phases can be identified. The changes between these phases are clearly demonstrated by the LEED spot intensities. Simultaneously, the Auger and XPS data show a decrease in Si intensity.

Interfacial Dislocations in (111) Ag-Cu Bilayers

1973 ◽  
Vol 31 ◽  
pp. 112-113
Author(s):  
C. T. Homg ◽  
R. W. Vook
Keyword(s):  
High Vacuum ◽  
Ultra High Vacuum ◽  
Two Dimensional ◽  
Double Diffraction ◽  
Cu Films ◽  
Interfacial Dislocations ◽  
Residual Gas ◽  
Diffraction Effects ◽  
Work Up

Smooth (111) single crystal Cu films (1200Å) were evaporated on NaCl/mica in an ultra-high vacuum RHEED systemI (base pressure ≤1×10−9 torr) The total residual gas pressure during Cu evaporation was less than 1×10−8 torr. These Cu films served as substrates for thin epitaxial monolayer Ag growth ranging in thickness from 1Å to 20Å, as measured by a quartz thickness monitor. These Ag-Cu bilayers were formed and examined in-situ in the RHEED system.The unusual RHEED patterns first re orted by Gradmann and Krause were observed in the present work up to l0Å of Ag. Beyond 10Å, only Ag and Cu lines plus double diffraction effects were detected. A typical example of the former is given in Fig. 1. The pattern was previously interpreted as due to a two dimensional grid of interfacial dislocations.

Electron induced surface reactions of (η5-C5H5)Fe(CO)2Mn(CO)5, a potential heterobimetallic precursor for focused electron beam induced deposition (FEBID)

2018 ◽  
Vol 20 (11) ◽  
pp. 7862-7874 ◽  
Author(s):  
Ilyas Unlu ◽  
Julie A. Spencer ◽  
Kelsea R. Johnson ◽  
Rachel M. Thorman ◽  
Oddur Ingólfsson ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Electron Beam ◽  
Photoelectron Spectroscopy ◽  
Surface Reactions ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
X Ray ◽  
Electron Beam Induced Deposition

Electron-induced surface reactions of (η5-C5H5)Fe(CO)2Mn(CO)5were exploredin situunder ultra-high vacuum conditions using X-ray photoelectron spectroscopy and mass spectrometry.

UHV Preparation and In-Situ Surface Analysis of MNFE/Nife Exchange Structures: Interfacial Impurity Incorporation

1993 ◽  
Vol 313 ◽  
Author(s):  
Susan L. Cohen ◽  
John M. Baker ◽  
Michael A. Russak ◽  
Gerald J. Scilla ◽  
Cherngye Hwang ◽  
...  
Keyword(s):  
Surface Analysis ◽  
Photoelectron Spectroscopy ◽  
Exchange Coupling ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Impurity Incorporation ◽  
X Ray ◽  
Manufacturing Applications ◽  
Analysis System

ABSTRACTMnFe/NiFe exchange structures have been prepared in an ultra-high vacuum sputtering/surface analysis system. Controlled introduction of residual gas impurities such as O2 and H2O at the MnFe/NiFe interface is studied by in-situ x-ray photoelectron spectroscopy (XPS) and the exchange structures are magnetically characterized. Due to the extreme reactivity of the NiFe surface towards O2, the exchange coupling is severely degraded by only small exposures of this molecule to the NiFe surface. In contrast, H2O does not oxidize the NiFe surface and therefore can be tolerated in greater quantities in the sputtering chamber without detrimental loss of exchange. This understanding of the basic surface chemistry of the MnFe and NiFe surfaces can lead to improved sputtering practices in actual manufacturing applications.

scholarly journals Direct-ARPES and STM Investigation of FeSe Thin Film Growth by Nd:YAG Laser

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 276
Author(s):  
Sandeep Kumar Chaluvadi ◽  
Debashis Mondal ◽  
Chiara Bigi ◽  
Jun Fujii ◽  
Rajdeep Adhikari ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Film Growth ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Single Crystal Surfaces ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Linearly Polarized ◽  
Tunnelling Microscopy ◽  
Quantum Materials

Research on ultrathin quantum materials requires full control of the growth and surface quality of the specimens in order to perform experiments on their atomic structure and electron states leading to ultimate analysis of their intrinsic properties. We report results on epitaxial FeSe thin films grown by pulsed laser deposition (PLD) on CaF2 (001) substrates as obtained by exploiting the advantages of an all-in-situ ultra-high vacuum (UHV) laboratory allowing for direct high-resolution surface analysis by scanning tunnelling microscopy (STM), synchrotron radiation X-ray photoelectron spectroscopy (XPS) and angle-resolved photoemission spectroscopy (ARPES) on fresh surfaces. FeSe PLD growth protocols were fine-tuned by optimizing target-to-substrate distance d and ablation frequency, atomically flat terraces with unit-cell step heights are obtained, overcoming the spiral morphology often observed by others. In-situ ARPES with linearly polarized horizontal and vertical radiation shows hole-like and electron-like pockets at the Γ and M points of the Fermi surface, consistent with previous observations on cleaved single crystal surfaces. The control achieved in growing quantum materials with volatile elements such as Se by in-situ PLD makes it possible to address the fine analysis of the surfaces by in-situ ARPES and XPS. The study opens wide avenues for the PLD based heterostructures as work-bench for the understanding of proximity-driven effects and for the development of prospective devices based on combinations of quantum materials.

A Novel Method for True Work Function Determination of Metal Surfaces by Combined Kelvin Probe and Photoelectric Effect Measurements

2000 ◽  
Vol 619 ◽  
Author(s):  
Bert Lägel ◽  
Iain D. Baikie ◽  
Konrad Dirscherl ◽  
Uwe Petermann
Keyword(s):  
Thin Film ◽  
Work Function ◽  
Metal Surfaces ◽  
Surface Condition ◽  
High Vacuum ◽  
Photoelectric Effect ◽  
Ultra High Vacuum ◽  
Kelvin Probe ◽  
Novel Method

ABSTRACTWe have developed a novel method for in-situ measurements of the true work function (ø) of metal surfaces by combined ultra-high vacuum compatible Kelvin Probe and photoelectric effect measurements. The work function is an extremely sensitive parameter of surface condition and can be used to study oxidation and thin film growth on metal surfaces. For example, the increase in ø due to oxidation of polycrystalline rhenium is 1.9eV.The Kelvin Probe measures local work function differences between a conducting sample and a reference tip in a non-contact, truly non-invasive way over a wide temperature range. However, it is an inherently relative technique and does not provide an absolute work function if the work function of the tip (øtip) is unknown.We present a novel approach to measure øtip with the Kelvin Probe via the photoelectric effect, using a Gd foil as the photoelectron source, hereby combining the advantages of both methods to provide the absolute work function of the sample surface. We demonstrate the application of the technique by in-situ work function measurements during oxidation of polycrystalline rhenium. The extended Kelvin Probe method therefore has potential applications as a characterisation tool for thin film epitaxy and work function engineering of surfaces.

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