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.

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.

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.

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.

Passivation of Gaas by Novel P2S5/(NH4)2Sx Sulfurization Techniques

1992 ◽  
Vol 281 ◽  
Author(s):  
J. T. Hsieh ◽  
C. Y. Sun ◽  
H. L. Hwang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Surface Passivation ◽  
Schottky Diodes ◽  
Lower Surface ◽  
State Density ◽  
Surface Band ◽  
Band Bending ◽  
Barrier Heights ◽  
Effective Barrier ◽  
Metal Work

ABSTRACTA new surface passivation technique using P2S5/(NH4)2S on GaAs was investigated, and the results are compared with those of the (NH4)2Sx treatment. With this new surface treatment, the effective barrier heights for both Al- and Au—GaAs Schottky diodes were found to vary with the metal work functions, which is a clear evidence of the lower surface state density. Results of I—V measurements show that P2S5/(NH4)2S—passivated diodes have lower reverse leakage current and higher effective barrier height than those of the (NH4)2Sx -treated ones. Auger Electron Spectroscopy, X—ray photoelectron spectroscopy and Raman scattering measurements were done to characterize the surfaces including their compositions and surface band bending. In this paper, interpretations on this novel passivation effect is also provided.

Surface Band Structure Studies of Si Rich Reconstructions on 4H-SiC(1-100)

2005 ◽  
Vol 483-485 ◽  
pp. 547-550 ◽  
Author(s):  
Konstantin V. Emtsev ◽  
Thomas Seyller ◽  
Lothar Ley ◽  
A. Tadich ◽  
L. Broekman ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Electron Diffraction ◽  
Photoelectron Spectroscopy ◽  
Low Energy ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
Surface Band ◽  
X Ray ◽  
Low Energy Electron Diffraction ◽  
Different Temperatures ◽  
Low Energy Electron

We have investigated Si-rich reconstructions of 4H-SiC( 00 1 1 ) surfaces by means of low-energy electron diffraction (LEED), x-ray photoelectron spectroscopy (XPS), and angleresolved ultraviolet photoelectron spectroscopy (ARUPS). The reconstructions of 4H-SiC( 00 1 1 ) were prepared by annealing the sample at different temperatures in a flux of Si. Depending on the temperature different reconstructions were observed: c(2×2) at T=800°C, c(2×4) at T=840°C. Both reconstructions show strong similarities in the electronic structure.

Band Bending at Heterovalent Interfaces: Hard X-ray Photoelectron Spectroscopy of GaP/Si(001) Heterostructures

2021 ◽  
pp. 150514
Author(s):  
O. Romanyuk ◽  
A. Paszuk ◽  
I. Bartoš ◽  
R.G. Wilks ◽  
M. Nandy ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Band Bending ◽  
X Ray

scholarly journals Band bending at the heterointerface of GaAs/InAs core/shell nanowires monitored by synchrotron X-ray photoelectron spectroscopy

2016 ◽  
Vol 120 (14) ◽  
pp. 145703 ◽  
Author(s):  
B. Khanbabaee ◽  
G. Bussone ◽  
J. V. Knutsson ◽  
I. Geijselaers ◽  
C. E. Pryor ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Core Shell ◽  
Band Bending ◽  
X Ray ◽  
Shell Nanowires
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