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.

Increased effective barrier heights in Schottky diodes by molecular‐beam epitaxy of CoSi2and Ga‐doped Si on Si(111)

1988 ◽  
Vol 64 (8) ◽  
pp. 4082-4085 ◽  
Author(s):  
R. W. Fathauer ◽  
T. L. Lin ◽  
P. J. Grunthaner ◽  
P. O. Andersson ◽  
J. M. Iannelli ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Schottky Diodes ◽  
Barrier Heights ◽  
Effective Barrier

Pt Schottky contacts on Ga- and N-face surfaces of free-standing GaN

2001 ◽  
Vol 680 ◽  
Author(s):  
U. Karrer ◽  
C.R. Miskys ◽  
O. Ambacher ◽  
M. Stutzmann
Keyword(s):  
Schottky Diodes ◽  
Reverse Current ◽  
Forward Direction ◽  
Hydride Vapor Phase Epitaxy ◽  
Free Standing ◽  
Band Bending ◽  
Barrier Heights ◽  
Consistent Solution ◽  
Lift Off ◽  
Gap States

ABSTRACTThick GaN films, grown by hydride vapor phase epitaxy (HVPE), were separated from their sapphire substrate with a laser-induced lift-off process. After cleaning and polishing, these films offer the most direct way to investigate and compare the influence of crystal polarity on the electronic properties of Ga-face and N-face surfaces, respectively. Different barrier heights for Pt Schottky diodes evaporated onto Ga- and N-face GaN are determined from the dependence of the effective barrier height versus ideality factor by I-V measurements to 1.15 eV and 0.80 eV, respectively. The charge neutrality condition at the surface is modified by the spontaneous polarization due to the polarization induced bound sheet charge. This effect has to be included in the electronegativity concept of metal induced gap states (MIGS) and can also be illustrated by different band bending of the conduction and valence band, inferred from the self-consistent solution of the Schrödinger-Poisson equation. Furthermore, temperature dependent I-V characteristics are compared to simulated behavior of Schottky diodes, exhibiting excellent agreement in forward direction, but showing deviations in the reverse current.

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.

scholarly journals Surface band bending in semimetal Td-WTe2

2020 ◽  
Author(s):  
Aixi Chen ◽  
Huifang Li ◽  
Rong Huang ◽  
Yanfei Zhao ◽  
Tong Liu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electric Polarization ◽  
Property A ◽  
Surface Band ◽  
Band Bending ◽  
Xps Spectra ◽  
Surface Polarization ◽  
Out Of Plane ◽  
Microscopic Origin ◽  
Ferroelectric Switching

Abstract Recently, spontaneous out-of-plane electric polarization and ferroelectric switching were found in WTe2 devices. On single crystal with ferroelectric property, a built-in electric field and corresponding band bending would be expected at the surface. However, such band bending in WTe2 hasn’t directly been observed experimentally. Here, by fitting angle-dependent X-ray photoelectron spectroscopy (XPS) spectra on WTe2 surface, we clearly observed downward band bending after slightly exposure to air, verifying appearance of surface polarization. Such band bending can’t be observed on pristine WTe2 surface and will disappear on fully oxidized sample. It suggests strong correlation between surface band bending and oxidation. Ionized donors from oxide species pinned at surface may contribute to the formation of surface band bending and polarization. Our study here offers new insight to figure out the microscopic origin of ferroelectric in WTe2.

Evolution of Ti Schottky Barrier Heights on n-Type GaN with Annealing

1996 ◽  
Vol 449 ◽  
Author(s):  
Michèle T. Hirsch ◽  
Kristin J. Duxstad ◽  
E. E. Haller
Keyword(s):  
Barrier Height ◽  
Schottky Diodes ◽  
Electron Beam Evaporation ◽  
Organic Vapor ◽  
Barrier Heights ◽  
Effective Barrier ◽  
Mott Model ◽  
Current Voltage ◽  
Metal Organic ◽  
Ti Films

ABSTRACTWe report the effect of mild annealing on Ti Schottky diodes on n-type GaN. The Ti films were deposited by electron beam evaporation on n-type GaN grown by metal organic vapor deposition. We determine the effective barrier height Ф60 by current-voltage measurements as a function of temperature. The as-deposited Ti contacts show rectifying behavior with low barrier heights Ф60 ≤ 200meV. At annealing temperatures as low as 60°C we observe an increase of the barrier height to values of 250meV. After annealing at 230°C and above a stable barrier height of 450meV is measured. The increase in barrier height is not due to any macroscopic interfacial reaction. The origin of the observed changes are discussed in terms of the Schottky-Mott model and possible microscopic interfacial reactions.

scholarly journals H-Terminated Diamond Surface Band Bending Characterization by Angle-Resolved XPS

Surfaces ◽  
2020 ◽  
Vol 3 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Gonzalo Alba ◽  
David Eon ◽  
M. Pilar Villar ◽  
Rodrigo Alcántara ◽  
Gauthier Chicot ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Vapour ◽  
Diamond Surface ◽  
Diamond Growth ◽  
Surface Band ◽  
Band Bending ◽  
New Approach ◽  
Shallow Acceptors ◽  
New Interpretation ◽  
P Type

Concerning diamond-based electronic devices, the H-terminated diamond surface is one of the most used terminations as it can be obtained directly by using H2 plasma, which also is a key step for diamond growth by chemical vapour deposition (CVD). The resultant surfaces present a p-type surface conductive layer with interest in power electronic applications. However, the mechanism for this behavior is still under discussion. Upward band bending due to surface transfer doping is the most accepted model, but has not been experimentally probed as of yet. Recently, a downward band bending very near the surface due to shallow acceptors has been proposed to coexist with surface transfer doping, explaining most of the observed phenomena. In this work, a new approach to the measurement of band bending by angle-resolved X-ray photoelectron spectroscopy (ARXPS) is proposed. Based on this new interpretation, a downward band bending of 0.67 eV extended over 0.5 nm was evidenced on a (100) H-terminated diamond surface.

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.

Quasi-Schottky Diodes on (n)In.53Ga.47as with Barrier Heights of 0.6 eV

1991 ◽  
Vol 240 ◽  
Author(s):  
M. Marso ◽  
P. Kordoš ◽  
R. Meyer ◽  
H. Lüth
Keyword(s):  
Schottky Barrier ◽  
Barrier Height ◽  
Schottky Diodes ◽  
Reverse Current ◽  
Surface Layers ◽  
Fully Depleted ◽  
Barrier Heights ◽  
Effective Barrier ◽  
Basic Parameters ◽  
And Control

ABSTRACTThe modification and control of the Schottky barrier height on (n)InGaAs is an important tool at the device preparation as the barrier height is very low, øB° = 0.2 eV. We report about the Schottky barrier enhancement on (n)InGaAs by thin fully depleted surface layers of high doped (p+)InGaAs. Structures with different thicknesses of (p+)InGaAs in the range from 8 to 80 nm were grown by LP MOVPE technique and quasi-Schottky diodes with different contact areas were prepared using titanium as a barrier metal. I-V and I-T characteristics were measured and analysed to obtain basic parameters of prepared diodes, i. e. ideality factor n, effective barrier height øB, series resistance Rgand reverse current density JR (1V). The barrier height enhancement increases with the thickness of the (p+)-layer. Effective barrier heights of øB>0.6 eV, i.e. higher than reported until now, can be obtained with the surface layers of (p+)InGaAs with thicknesses exceeding 25 nm.

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.

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