Surface Electronic Structure of Nitric-oxide-treated Indium Tin Oxide

2003 ◽  
Vol 796 ◽  
Author(s):  
Hu Jianqiao ◽  
Pan Jisheng ◽  
Furong Zhu ◽  
Gong Hao
Keyword(s):  
Nitric Oxide ◽  
Binding Energy ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Surface Region ◽  
Valence Band Maximum ◽  
Surface Band ◽  
Band Bending ◽  
Surface Electronic Structure

ABSTRACTThe surface electronic properties of the nitric oxide (NO) treated indium tin oxide (ITO) are examined in-situ by a four-point probe and X-ray photoelectron spectroscopy (XPS). The XPS N1s peak emerged at a high binding energy of 404 eV indicating that NO is reactive with ITO. NO adsorption induces an increase of film sheet resistance, arising from an oxygen rich layer near the ITO surface region, with approximately 2.5 nm thick. This implies that the interaction of NO with ITO is occurred around surface region. Valence band maximum measured for NO-absorbed ITO was shifted to the low binding energy side. This is related to the upward surface band bending.

Evidence of nitric-oxide-induced surface band bending of indium tin oxide

2004 ◽  
Vol 95 (11) ◽  
pp. 6273-6276 ◽  
Author(s):  
Jianqiao Hu ◽  
Jisheng Pan ◽  
Furong Zhu ◽  
Hao Gong
Keyword(s):  
Nitric Oxide ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Surface Band ◽  
Band Bending

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.

Anodic sulfidation and model characterisation of GaAs (100) in (NH4)2 Sx solution

1999 ◽  
Vol 573 ◽  
Author(s):  
R. F. Elbahnasawy ◽  
J. G. Mclnerney ◽  
P. Ryan ◽  
G. Hughes ◽  
M. Murtagh
Keyword(s):  
Photoelectron Spectroscopy ◽  
Structural Model ◽  
Thick Layer ◽  
Surface Region ◽  
Optoelectronic Device ◽  
Native Oxide ◽  
Surface Barrier ◽  
Surface Band ◽  
Band Bending ◽  
Near Surface

ABSTRACTElectrochemical sulfidation of n-type GaAs (100) has been investigated under anodic conditions with a view to surface passivation for improved electronic and optical properties. This treatment has successfully removed the native oxide and formed a thick layer of gallium and arsenic sulfides displaying high durability against oxidation and optical degradation compared to conventional dipping treatment using (NH4)2S solution. X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), secondary ion mass spectroscopy (SIMS) and atomic force microscopy (AFM) have been used to characterize the treated surfaces. These studies have been used to devise a structural model of the near-surface region. The results of Raman backscattering spectroscopy measurements indicate that there is a 35% reduction of the surface barrier height compared to the untreated surface. This passivation technique has been shown to be effective in reducing surface band bending on GaAs (100) and enhancing the chemical stability of the surface, making it more suitable for electronic and optoelectronic device applications.

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.

X-ray photoelectron spectroscopy studies of indium tin oxide nanocrystalline powder

2005 ◽  
Vol 54 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Bagas Pujilaksono ◽  
Uta Klement ◽  
Lars Nyborg ◽  
Urban Jelvestam ◽  
Sven Hill ◽  
...  
Keyword(s):  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Photoelectron Spectroscopy ◽  
Nanocrystalline Powder ◽  
X Ray ◽  
Spectroscopy Studies

Electronic Properties of Chemically Etched CdTe Thin Films: Role of Te for Back-Contact Formation

2001 ◽  
Vol 668 ◽  
Author(s):  
D. Kraft ◽  
A. Thiβen ◽  
M. Campo ◽  
M. Beerbom ◽  
T. Mayer ◽  
...  
Keyword(s):  
Fermi Level ◽  
Electronic Properties ◽  
Photoelectron Spectroscopy ◽  
Valence Band Maximum ◽  
Ex Situ ◽  
Back Contact ◽  
Experimental Conditions ◽  
Band Bending ◽  
Fermi Level Position ◽  
Contact Formation

ABSTRACTImprovement of electric back contact formation is one of the major issues of the CdTe thin film solar cell research. Chemical etching of CdTe before metallization is accepted to improve contact formation. It is believed that a CdTe/Te contact is formed by this procedure leading to a Fermi level position in the CdTe close to the valence band maximum for low contact resistance. We have studied the electronic properties of chemically etched CdTe surfaces with photoelectron spectroscopy. Etching of the samples was performed in air (“ex-situ“) as well as in an electrochemical setup directly attached to the UHV system (“in-situ“). The formation of a Te layer is clearly shown by (S)XPS. In contrast to previous studies we could not detect the formation of a p-CdTe surface for different experimental conditions. The detected Fermi level position indicates still band bending and hence a blocking Schottky barrier.

Sensing Characteristics of Cubic and Rhombohedral Nanocrystalline ITO Thick Films

2001 ◽  
Vol 704 ◽  
Author(s):  
Jeung-Soo Huh ◽  
Bong-Chull Kim ◽  
Jae-Yeol Kim ◽  
Jeong-Ok Lim
Keyword(s):  
Crystal Structure ◽  
Particle Size ◽  
Binding Energy ◽  
Surface Structure ◽  
Crystal Structures ◽  
Aging Time ◽  
Tin Oxide ◽  
Indium Tin Oxide ◽  
Ethanol Sensing ◽  
Sensing Characteristics

AbstractTwo kinds of nanocrystalline Tin doped indium oxide (or indium tin oxide: denoted ITO hereafter) powders with different crystal structures – rhombohedral and cubic – were prepared using a coprecipitation method through the control of pH of a mixing solution and aging time after coprecipitation. The two powders have the same particle size of 15 nm in diameter but different morphologies (spherical for rhomboheral and rectangular for cubic). The gaseous ethanol sensing characteristics of the sensors prepared by the two ITO powders were quite different. The sensitivity of rhombohedral ITO sensor was high compared to that of the cubic ITO sensor across all temperatures. The reason for this is explained through the viewpoint of the binding energy of XPS and the surface structure relating to the crystal structure.

Role of Surfaces and Interfaces for the Electronic Properties of Conducting Oxides

2001 ◽  
Vol 666 ◽  
Author(s):  
Andreas Klein
Keyword(s):  
Work Function ◽  
Electronic Properties ◽  
Photoelectron Spectroscopy ◽  
Band Alignment ◽  
Surface Band ◽  
Band Bending ◽  
Conducting Oxides ◽  
Degenerate Semiconductors ◽  
Surfaces And Interfaces

ABSTRACTTransparent conductive oxides (TCOs) are generally considered as degenerate semiconductors doped intrinsically by oxygen vacancies and by intentionally added dopants. For some applications a high work function is required in addition to high conductivity and it is desired to tune both properties independently. To increase the work function, the distance between the Fermi energy and the vacuum level must increase, which can be realized either by electronic surface dipoles or by space charge layers. Photoelectron spectroscopy data of in-situ prepared samples clearly show that highly doped TCOs can show surface band bending of the order of 1 eV. It is further shown that the band alignment at heterointerfaces between TCOs and other materials, which are crucial for many devices, are also affected by such band bending. The origin of the band bending, which seems to be general to all TCOs, depends on TCO thin film and surface processing conditions. The implication of surface band bending on the electronic properties of thin films and interfaces are discussed.

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