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.

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.

scholarly journals Оптические и электронные свойства пассивированных поверхностей InP(001)

2021 ◽  
Vol 55 (8) ◽  
pp. 644
Author(s):  
П.А. Дементьев ◽  
Е.В. Дементьева ◽  
Т.В. Львова ◽  
В.Л. Берковиц ◽  
М.В. Лебедев
Keyword(s):  
Aqueous Solution ◽  
Electronic Properties ◽  
Surface Region ◽  
Alcoholic Solution ◽  
Surface Band ◽  
Band Bending ◽  
Near Surface ◽  
Ammonium Sulfide ◽  
Optical And Electronic Properties ◽  
Chemical Passivation

The effect of chemical passivation in solutions of ammonium sulfide (NH4)2S on the optical and electronic properties of the n-InP (001) surface has been studied. It has been shown that treatment in a 4% aqueous solution of (NH4)2S leads to a decrease of surface band bending and localized charges in near-surface region in the 2 times. Processing in a 4% alcoholic solution of (NH4)2S leads to a decrease in these parameters in 3 times, and moreover, the barrier photovoltage and also reduces in three times.

The Effect of Surface States on Secondary Electron (SE) Dopant Contrast from Silicon p-n Junctions

2007 ◽  
Vol 1026 ◽  
Author(s):  
Augustus K. W. Chee ◽  
Conny Rodenburg ◽  
Colin John Humphreys
Keyword(s):  
Oxide Layer ◽  
Computer Modelling ◽  
Surface States ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Element Analysis ◽  
Surface Band ◽  
Band Bending ◽  
Wide Range ◽  
Se Doping

AbstractDetailed computer modelling using finite-element analysis was performed for Si p-n junctions to investigate the effects of surface states and doping concentrations on surface band-bending, surface junction potentials and external patch fields. The density of surface states was determined for our Si specimens with a native oxide layer. Our calculations show that for a typical density of surface states for a Si specimen with a native oxide layer, the effects of external patch fields are negligible and the SE doping contrast is due to the built-in voltage across the p-n junction modified by surface band-bending. There is a good agreement between the experimental doping contrast and the calculated junction potential just below the surface, taking into account surface states, for a wide range of doping concentrations.

Effect of near-surface band bending on dopant profiles in ion-implanted silicon

2004 ◽  
Vol 95 (3) ◽  
pp. 1134-1140 ◽  
Author(s):  
Michael Y. L. Jung ◽  
Rudiyanto Gunawan ◽  
Richard D. Braatz ◽  
E. G. Seebauer
Keyword(s):  
Surface Band ◽  
Band Bending ◽  
Near Surface ◽  
Dopant Profiles ◽  
Ion Implanted

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.

Revealing the mechanism of the early stages of Ni–W RABiTS oxidation

2010 ◽  
Vol 25 (12) ◽  
pp. 2362-2370 ◽  
Author(s):  
Andrey V. Blednov ◽  
Oleg Yu. Gorbenko ◽  
Dmitriy P. Rodionov ◽  
Andrey R. Kaul
Keyword(s):  
Internal Oxidation ◽  
Photoelectron Spectroscopy ◽  
Oxidation Mechanism ◽  
Surface Oxidation ◽  
Surface Region ◽  
Near Surface ◽  
Precise Position ◽  
X Ray ◽  
Early Stages ◽  
Phase And Chemical Composition

The early stages of surface oxidation of biaxially textured Ni–W tapes were studied using thermodynamic calculations along with experimental tape oxidation at low P(O2). Tape phase and chemical composition, surface morphology, and roughness were examined using x-ray diffraction (XRD), energy-dispersive x-ray analysis (EDX), secondary ion mass spectroscopy (SIMS), x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). For a Ni0.95W0.05 alloy tape, the precise position of the tape oxidation line in P(O2)–T coordinates was established. This line includes a break at T ≈ 650 °C that originates from the change of the W oxidation mechanism from internal oxidation to oxidation on a free surface accompanied by segregation of the alloy components in the tape near-surface region. The surface roughness of a polished tape increased drastically during internal oxidation of W; further tape oxidation did not affect the integral roughness parameters, but introduced numerous small (˜;100 nm) features on the tape surface comprising NiO precipitates.

scholarly journals Microstructure and Mechanical Properties of Ti + N Ion Implanted Cronidur30 Steel

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 427 ◽  
Author(s):  
Jie Jin ◽  
Wei Wang ◽  
Xinchun Chen
Keyword(s):  
Mechanical Properties ◽  
Ion Implantation ◽  
Photoelectron Spectroscopy ◽  
Structural Modification ◽  
Surface Region ◽  
Grazing Incidence ◽  
Bearing Steel ◽  
Near Surface ◽  
X Ray ◽  
Ion Implanted

In this study, Ti + N ion implantation was used as a surface modification method for surface hardening and friction-reducing properties of Cronidur30 bearing steel. The structural modification and newly-formed ceramic phases induced by the ion implantation processes were investigated by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and grazing incidence X-ray diffraction (GIXRD). The mechanical properties of the samples were tested by nanoindentation and friction experiments. The surface nanohardness was also improved significantly, changing from ~10.5 GPa (pristine substrate) to ~14.2 GPa (Ti + N implanted sample). The friction coefficient of Ti + N ion implanted samples was greatly reduced before failure, which is less than one third of pristine samples. Furthermore, the TEM analyses confirmed a trilamellar structure at the near-surface region, in which amorphous/ceramic nanocrystalline phases were embedded into the implanted layers. The combined structural modification and hardening ceramic phases played a crucial role in improving surface properties, and the variations in these two factors determined the differences in the mechanical properties of the samples.

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.

An Examination of Kernite (Na2B4O6(OH)2·3H2O) Using X-Ray and Electron Spectroscopies: Quantitative Microanalysis of a Hydrated Low-Z Mineral

2011 ◽  
Vol 17 (5) ◽  
pp. 718-727 ◽  
Author(s):  
Douglas C. Meier ◽  
Jeffrey M. Davis ◽  
Edward P. Vicenzi
Keyword(s):  
Electron Beam ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Stoichiometric Composition ◽  
Surface Region ◽  
Variable Pressure ◽  
Sampling Depth ◽  
Electrical Insulator ◽  
Near Surface ◽  
X Ray

AbstractMineral borates, the primary industrial source of boron, are found in a large variety of compositions. One such source, kernite (Na2B4O6(OH)2·3H2O), offers an array of challenges for traditional electron-probe microanalysis (EPMA)—it is hygroscopic, an electrical insulator, composed entirely of light elements, and sensitive to both low pressures and the electron beam. However, the approximate stoichiometric composition of kernite can be analyzed with careful preparation, proper selection of reference materials, and attention to the details of quantification procedures, including correction for the time dependency of the sodium X-ray signal. Moreover, a reasonable estimation of the mineral's water content can also be made by comparing the measured oxygen to the calculated stoichiometric oxygen content. X-ray diffraction, variable-pressure electron imaging, and visual inspection elucidate the structural consequences of high vacuum treatment of kernite, while Auger electron spectroscopy and X-ray photoelectron spectroscopy confirm electron beam-driven migration of sodium and oxygen out of the near-surface region (sampling depth ≈ 2 nm). These surface effects are insufficiently large to significantly affect the EPMA results (sampling depth ≈ 400 nm at 5 keV).

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