scholarly journals Precise determination of surface band bending in Ga-polar n-GaN films by angular dependent X-Ray photoemission spectroscopy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yanfei Zhao ◽  
Hongwei Gao ◽  
Rong Huang ◽  
Zengli Huang ◽  
Fangsen Li ◽  
...  
Keyword(s):  
Electrostatic Potential ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
Core Level ◽  
Level Energy ◽  
Linear Potential ◽  
Surface Band ◽  
Band Bending ◽  
X Ray ◽  
Bending Effect

AbstractWe present a systematic study of surface band bending in Ga-polar n-GaN with different Si doping concentrations by angular dependent X-ray photoelectron spectroscopy (ADXPS). The binding energies of Ga 3d and N 1 s core levels in n-GaN films increase with increasing the emission angle, i. e., the probing depth, suggesting an upward surface band bending. By fitting the Ga 3d core level spectra at different emission angles and considering the integrated effect of electrostatic potential, the core level energy at the topmost surface layer is well corrected, therefore, the surface band bending is precisely evaluated. For moderately doped GaN, the electrostatic potential can be reflected by the simply linear potential approximation. However, for highly doped GaN samples, in which the photoelectron depth is comparable to the width of the space charge region, quadratic depletion approximation was used for the electrostatic potential to better understand the surface band bending effect. Our work improves the knowledge of surface band bending determination by ADXPS and also paves the way for studying the band bending effect in the interface of GaN based heterostructures.

scholarly journals On the prediction of core level binding energies in molecules, surfaces and solids

2018 ◽  
Vol 20 (13) ◽  
pp. 8403-8410 ◽  
Author(s):  
Francesc Viñes ◽  
Carmen Sousa ◽  
Francesc Illas
Keyword(s):  
Photoelectron Spectroscopy ◽  
State Of The Art ◽  
Binding Energies ◽  
Core Level ◽  
Chemical Environment ◽  
X Ray ◽  
Unique Information

Core level binding energies, measured by X-ray photoelectron spectroscopy providing unique information regarding the chemical environment of atoms in a system, can be estimated by a diversity of state-of-the-art accurate methods here detailed.

Characterization of Oxidized Nickel (II) Dimethylglyoxime Using X-Ray Photoelectron Spectroscopy

1987 ◽  
Vol 41 (6) ◽  
pp. 994-1000 ◽  
Author(s):  
V. Y. Young ◽  
F. C. Chang ◽  
K. L. Cheng
Keyword(s):  
Oxidation State ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
Core Level ◽  
Solution Phase ◽  
Intensity Data ◽  
X Ray ◽  
Complex Core

X-ray photoelectron spectroscopy has been used to determine the oxidation state of nickel in the oxidized nickel (II) dimethylglyoxime complex. Core level binding energies for the Ni(2p), N(1s), and O(1s) levels; the presence or absence of shake-up satellites on the Ni(2p) levels; and the analysis of intensity data are consistent only with an assignment of +3. Structures consistent with the data are proposed for both the solid-and the solution-phase complexes.

Impurities in SiO2: Atomic States of Phosphorus and Arsenic

1986 ◽  
Vol 82 ◽  
Author(s):  
H. E. Rhodes ◽  
G. Apai
Keyword(s):  
Binding Energy ◽  
Silicon Dioxide ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
Core Level ◽  
X Ray ◽  
Impurity Atoms ◽  
Atomic States ◽  
Energy Signal ◽  
State 1

ABSTRACTWe have studied the atomic states of arsenic (As) and phosphorus (P) in SiO2 using X-ray photoelectron spectroscopy (XPS). Silicon dioxide implanted with As or P shows multiple XPS core level peaks corresponding to the impurity atoms located in two distinct atomic sites. The binding energies of the two arsenic 3d core levels occur at 45.8 and 42.3 eV and the two phosphorus 2p core levels occur at 134.7 and 130.3 eV. When the implanted oxides are annealed in an oxygen ambient between 900°C and 950°C, only the highbinding- energy peaks of P and As are observed. This identifies the highbinding- energy core level peaks as being associated with the impurity (P or As) on silicon sites. Annealing in nitrogen at 950° C results in an increase in the low-binding-energy signal. The low-binding-energy peaks are associated with the impurity (P or As) bonded to silicon neighbors. The relative amounts of dopants in silicon and oxygen sites depend on ambient purity and processing details. Reference to previous work shows that the presence of As or P on silicon sites in SiO2 corresponds to a fast diffusing state whereas As or P on oxygen sites corresponds to a slow diffusing state [1].

scholarly journals Core-Level Photoemission From Stoichiometric GaN(0001)-1×1

2005 ◽  
Vol 10 ◽  
Author(s):  
S.M. Widstrand ◽  
K.O. Magnusson ◽  
L.S.O. Johansson ◽  
E. Moons ◽  
M. Gurnett ◽  
...  
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
Core Level ◽  
Complex Structures ◽  
Dangling Bond ◽  
X Ray ◽  
The Core ◽  
Slight Excess ◽  
Bulk Gan

We report on a high-resolution x-ray photoelectron spectroscopy (HRXPS) study using synchrotron radiation, for the identification of the core level binding energies of Ga 3d and N 1s, from a stoichiometric Ga-polar GaN(0001)-1×1 sample.Three surface shifted components were found on the stoichiometric surface for the Ga 3d feature. The first surface shifted component has a higher binding energy of 0.85 eV, and is interpreted as surface Ga with one of the N bonds replaced by an empty dangling bond. This structure is belonging to the stoichiometric clean and ordered Ga-polar GaN(0001)-1×1 surface. The second, with a binding energy relative the bulk of −0.76 eV, is interpreted as Ga with one of the bonds to a Ga atom, which indicates a slight excess of Ga on the surface. The third surface shifted component is shifted by 2.01 eV and is related to gallium oxide in different configurations.The N 1s feature is complex with five surface shifted components relative the bulk were found. Two components with binding energy shifts of −0.54 eV and 0.47 eV are interpreted as surface shifted core levels from the stoichiometric, clean Ga-polar GaN(0001)-1×1 surface.We also analysed the Ga 3d spectrum after deposition of 1.5 ML of Ga on a stoichiometric surface. The surface shift for the Ga 3d5/2 component from the Ga overlayer is −1.74 eV relative the bulk GaN.The C 1s and O 1s core levels from remaining surface contamination have also been line shaped analysed and show complex structures.

scholarly journals Influences of ALD Al2O3 on the surface band-bending of c-plane, Ga-face GaN

2021 ◽  
Author(s):  
Jiarui Gong ◽  
Kuangye Lu ◽  
Jisoo Kim ◽  
Tien Khee Ng ◽  
Donghyeok Kim ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Band ◽  
Band Bending ◽  
X Ray ◽  
The Poor ◽  
P Type

Abstract The recently demonstrated approach of grafting n-type GaN with p-type Si or GaAs, by employing ultrathin Al2O3 at the interface, has shown the feasibility to overcome the poor p-type doping challenge of GaN. However, the surface band-bending of GaN that could be influenced by the Al2O3 has been unknown. In this work, the band-bending of c-plane, Ga-face GaN with ultrathin Al2O3 deposition at the surface of GaN was studied using X-ray photoelectron spectroscopy (XPS). The study shows that the Al2O3 can help suppress the upward band-bending of the c-plane, Ga-face GaN with a monotonic reduction trend from 0.48 eV down to 0.12 eV as the number of Al2O3 deposition cycles increases from 0 to 20. The study further shows that the band-bending can be mostly recovered after removing the Al2O3 layer, concurring that the introduction of ultrathin Al2O3 is the main reason for the surface band-bending modulation.

The effect of covalently bonded aryl layers on the band bending and electron density of SnO2 surfaces probed by synchrotron X-ray photoelectron spectroscopy

2019 ◽  
Vol 21 (32) ◽  
pp. 17913-17922 ◽  
Author(s):  
Joel C. Schuurman ◽  
Alexandra R. McNeill ◽  
Rodrigo F. Martinez-Gazoni ◽  
Jonty I. Scott ◽  
Roger J. Reeves ◽  
...  
Keyword(s):  
Electron Density ◽  
Photoelectron Spectroscopy ◽  
Surface Band ◽  
Band Bending ◽  
X Ray ◽  
Covalently Bonded

A downward to upward surface band bending change can be induced by grafted 4-(trifluoromethyl)phenyl groups on SnO2.

An angular dependent X-ray photoemission study of Indium-tin-oxide surfaces

2002 ◽  
Vol 747 ◽  
Author(s):  
H. H. Fong ◽  
W. J. Song ◽  
S. K. So
Keyword(s):  
Work Function ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Surface Band ◽  
Band Bending ◽  
X Ray ◽  
Plasma Treatments ◽  
Photoemission Study ◽  
Uv Ozone

ABSTRACTThe surface properties of indium-tin-oxide (ITO) thin films treated by UV ozone or plasma were analyzed by angular dependent X-ray photoelectron spectroscopy (ADXPS) and by ultraviolet photoemission (UPS). The chemical composition, chemical states and the work function of the ITO surfaces were deduced. Our analysis indicate that ITO surface is Sn-rich. Both UV ozone and O-plasma treatments are most effective in removing surface hydrocarbon. Among all treatments, O-plasma treated surface achieved the highest work function of 4.4eV, whereas argon ion sputtered surface had the lowest work function of 3.9eV. Both O-plasma and UV ozone treatments increase the surface oxygen concentration. It is proposed that O2-ions diffuse into ITO. The diffusion length is about 50Å as deduced from ADXPS. The stoichiometry of the surface is the major factor in controlling the surface work function of ITO. A surface band bending model is proposed to account for the change of work function due to “oxidized” ITO surface after UV-ozone or oxygen plasma treatments.

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