Detailed x‐ray photoelectron spectroscopy valence band and core level studies of select metals oxidations

1992 ◽  
Vol 10 (4) ◽  
pp. 2383-2390 ◽  
Author(s):  
Tery L. Barr ◽  
Mengping Yin ◽  
Shikha Varma
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Core Level ◽  
X Ray

Compositionally Dependent Band Offsets In Aln/AlxGa1-xN Heterojunctions Measured By Using X-Ray Photoelectron Spectroscopy

1997 ◽  
Vol 482 ◽  
Author(s):  
R.A. Beach ◽  
E.C. Piquette ◽  
R.W. Grant ◽  
T.C. McGill
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Valence Band Maximum ◽  
Core Level ◽  
Band Offset ◽  
Valence Band Offset ◽  
Band Offsets ◽  
Band Maximum ◽  
X Ray ◽  
Al Content

AbstractAlthough GaN has been extensively studied for applications in both light emitting and high power devices, the AlN/GaN valence band offset remains an area of contention. Values quoted in the literature range from 0.8eV (Martin)[1] to 1.36eV (Waldrop)[2]. This paper details an investigation of the AIN/AlxGa1-xN band offset as a function of alloy composition. We find an AlN/AlxGa1-xN valence band offset that is nearly linear with Al content and an end point offset for AlN/GaN of 1.36 ± 0.1 eV. Samples were grown using radio frequency plasma assisted molecular beam epitaxy and characterized with x-ray photoelectron spectroscopy(XPS). Core-level and valence-band XPS data for AIN (0001) and AlxGa1-xN (0001) samples were analyzed to determine core-level to valence band maximum (VBM) energy differences. In addition, oxygen contamination effects were tracked in an effort to improve accuracy. Energy separations of core levels were obtained from AlN/AlxGa1-xN(0001) heterojunctions. From this and the core-level to valence band maximum separations of the bulk materials, valence band offsets were calculated.

Spin-Resolved Photoemission Study of n = 2 Core Levels of Iron

1993 ◽  
Vol 313 ◽  
Author(s):  
L.E. Klebanoff ◽  
D.G. Van Campen ◽  
R.J. Pouliot
Keyword(s):  
Valence Band ◽  
Photoelectron Spectroscopy ◽  
Core Level ◽  
X Ray ◽  
Photoemission Study

ABSTRACTThe first spin-resolved x-ray photoelectron spectroscopy (SRXPS) study of the n = 2 core levels of ferromagnetic Fe are reported. The 2p3/2, 2p1/2 and 2s core levels all display interesting spin-dependent structures and splittings. The spectral complexity predicted by a purely atomic picture is not observed in the data. The results indicate that theories incorporating the delocalization of the 3d valence band are more applicable to the description of core-level photoemission in iron.

Valence Band Alignment of Ultra-Thin SiO2/Si Interfaces As Determined By High Resolution X-Ray Photoelectron Spectroscopy

1995 ◽  
Vol 386 ◽  
Author(s):  
J. L. Alay ◽  
M. Fukuda ◽  
C. H. Bjorkman ◽  
K. Nakagawa ◽  
S. Sasaki ◽  
...  
Keyword(s):  
High Resolution ◽  
Valence Band ◽  
Density Of States ◽  
Photoelectron Spectroscopy ◽  
Oxide Thickness ◽  
Core Level ◽  
Band Alignment ◽  
X Ray ◽  
Charging Effect

ABSTRACTUltra-thin SiO2/Si(111) interfaces have been studied by high resolution x-ray photoelectron spectroscopy. The deconvolution of the Si 2p core-level peak reveals the presence of the suboxide states Si3+ and Si1+ and the nearly complete absence of Si2+. The energy shifts found in the Si 2p and O is core-level peaks arising from charging effects arc carefully corrected. The valence band density of states for ultra-thin (1.8 - 3.7 nm thick) SiO2 is obtained by subtracting the bulk Si contribution from the measured spcctrum and by taking into account the charging effect of SiO2 and bulk Si. Thus obtained valence band alignment of ultra-thin SiO2/Si(111) interfaces is found to be 4.36 ± 0.10 eV regardless of oxide thickness.

X-Ray Photoelectron Spectroscopic Studies of Carbon Fiber Surfaces. Part XVI: Core-Level and Valence-Band Studies of Pitch-Based Fibers Electrochemically Treated in Ammonium Carbonate Solution

1992 ◽  
Vol 46 (4) ◽  
pp. 645-651 ◽  
Author(s):  
Yaoming Xie ◽  
Tiejun Wang ◽  
Oliver Franklin ◽  
Peter M. A. Sherwood
Keyword(s):  
Carbon Fiber ◽  
Valence Band ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Treatment Time ◽  
Spectroscopic Studies ◽  
Core Level ◽  
Short Treatment ◽  
X Ray ◽  
Band Spectra

DuPont E-120 high-modulus pitch-based carbon fibers were treated electrochemically in 0.5 M (NH4)2CO3 solution under both potentiostatic and galvanostatic modes. X-ray photoelectron spectroscopy (XPS) was used to monitor the chemical changes on the carbon fiber surfaces. Both core-level and valence-band spectra showed that the treatment introduced both oxygen-containing and nitrogen-containing functional groups onto the fiber surfaces, and the mainly oxygen-containing functional groups produced were carbonyl (C=O) type functional groups after longer treatment time. For short treatment time, hydroxide (C-OH) type groups were the dominant functionality, and ether (C-O-C) or epoxide type groups were also formed. The O 2 s peaks from oxygen atoms in the hydroxide functionality and the ether or epoxide groups are well separated in the valence-band spectra; the corresponding O 1 s peaks, however, are not separated in the O 1 s core-region spectra.

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