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In this paper, trends in work function values of transition metal carbides and nitrides are examined using results from semi-empirical method, theoretical method with Jerrium model and first-principles calculations.
- Series Editor
- Editorial Board
- TEM
- Plasma
- 1.2 Contents of the Following Chapters
- 2.2 Origin of the Work Function
- 3.1.1 Substitutional Alloys
- 3.1.4 Two Elements with Miscibility Gap
- 3.3 Adsorption or Segregation
- 4.4 Other Methods
- Modification of Band Alignment via Work Function Control
- 5.1 Ideal Band Alignment
- EVAC
- n-semiconductor
- n-semiconductor
- VFB φm − φs.
- SBH EC EF E
- EA
- 6.2 Origin of Nonideality
- 6.2.2 Disorder-Induced Gap States (DIGS) Model
- + |tm 2MoccNCB
- Utilization of Interface Potential
- VB
Naoki OHASHI, National Institute for Materials Science, Tsukuba, Ibaraki, Japan
Takahito OHMURA, National Institute for Materials Science, Tsukuba, Ibaraki, Japan Yoshitaka TATEYAMA, National Institute for Materials Science, Tsukuba, Ibaraki, Japan Takashi TANIGUCHI, National Institute for Materials Science, Tsukuba, Ibaraki, Japan Kazuya TERABE, National Institute for Materials Science, Tsukuba, Ibaraki, Japan Masanobu NAITO,...
Electron lithography Photo-detector Fluorescent plug
Fig. 1.3 Applications related to electron emission phenomena. See text for explanation signs, and car plugs. For these applications, electron emission is mostly utilized to initiate electric discharge. Electric discharge initiated by electron emission is used for plasma formation, and plasma is utilized for many industrial applications such as film...
As briefly overviewed in the above section, the work function plays an important role in a very wide range of scientific, technological, and industrial fields. In the following chapters, we discuss the physical origin of the work function, how the work function can be controlled on the basis of physics, and how to design interfaces. In this section...
The work function is the potential barrier that binds electrons inside a material. Therefore, we start by considering the energy stabilization of electrons by bond formation between atoms. When two atoms approach each other, a bonding orbital and an anti-bonding orbital are generated as a result of overlap of the wave functions of valence electrons...
Basically, a metal with a low melting point has a low work function. Because the melting point is a quantity that represents the strength of atomic bonding, which is a parameter that reflects the bulk term of the work function, a low-melting-point metal is expected to have a smaller work function. Similarly, weak atomic bonding results in a low sur...
There are combinations where two metals do not mix but separate, forming a misci-bility gap in the phase diagram. The composition dependence of the work function exhibits specific features in accordance with the miscibility gap. The characteristic feature of this type of binary system is that the work function is insensitive to the composition in t...
One of most frequently applied techniques for modifying the work function is to adsorb a second metal on the mother surface. Adsorbates on the surface change the electron distribution at the surface and modify the surface term of the work function while maintaining the bulk term of the material. “Adsorption” is the term used when the adsorbate atom...
There are many other methods of measuring the work function, both old and new. Here,adistinctiveindirectmethodcalledthephotoemissionofadsorbedxenon(PAX) is described because its measurement principle is considerably different from those of the above methods and it is still utilized for some specific measurements.
In this chapter, the band alignment in an ideal case will be discussed. Ideally, the band alignment is solely determined by the work functions of the materials in contact. In many cases, however, the interface band alignment deviates from the ideal condition for many intrinsic and extrinsic reasons. Even in such nonideal cases, an ideal contact is ...
The band alignment between a metal (work function of φm) and an n-type semicon-ductor (work function of φs) in an ideal case is shown in Fig. 5.1. Similarly to the surface discussed in Chap. 2 (Fig. 2.8a), the electron distribution at an edge where the surrounding electric condition changes sharply deviates from that in a uniform region, forming an...
EF n-semiconductor EA E VAC IP E C E F EV SBH E VAC EA EVAC - EA
gate insulator drain V VAC E n-semiconductor EF EVAC EA
MOS (see text for explanation) VAC E F E EA EVAC ΔE EC EF EV ΔE = - Flat band
Similar to the case of metal–semiconductor interfaces, the above equation is not satisfied in many practical systems. Therefore, the effective work function in this case is determined by the equation
F EV Band diagram of interface with inseron of interface layer of metal B EVAC EF EVAC EA EVAC EC
Amorphous and/or nanocrystal Si Amorphous and/or nanocrystal Si EVAC
Many ideas have been proposed to explain nonideality from different viewpoints. One viewpoint is that the origin of nonideality is either intrinsic or extrinsic. Here, an “intrinsic origin” means that nonideality originates from the nature of the mate-rials and cannot be changed by changing the process of interface formation. On the other hand, an ...
The concept of the DIGS model is that disorder in the atomic arrangement is intro-duced at the interface upon interface formation, which breaks the periodicity and generates gap states in the band gap. In some cases, disorder might be introduced unintentionally, i.e., a disordered arrangement in the thermodynamic equilibrium state. In other cases, ...
− CB| − This means that the position of the generalized CNL is intrinsic and dependent on the combination of the metal and oxide, so the S parameter, which is the slope in the φm versus SBH plot, no longer applies. This model is useful for explaining the phenomena but cannot predict the SBH in advance without calculating all the transfer energies a...
The discussion in Chap. 6 revealed that the interface potential gap and the S parameter determine how the band is aligned at the interface by modifying the work function of a metal. When the terminating species of a semiconductor (or insulator) changes at the interface depending on the metals in contact, the concept of the S parameter no longer app...
Zn term metal E F CB p-SBH VB contact, enabling the tuning of the SBH by work function modification. Note that the thermodynamic stability of interface termination must be considered in the control of interface-terminating species for band alignment.
- Michiko Yoshitake
- 2020
Michiko YOSHITAKE, Chief researcher | Cited by 1,632 | | Read 216 publications | Contact Michiko YOSHITAKE
Libra, Petr Hanyš, Karel Mašek, Michiko Yoshitake, Vladimír Matolín, Appl.Surf.Sci., 254, 2007, 490-493 - Vacuum vapour deposition of phenylphosphonic acid on amorphous alumina, N. Tsud and M. Yosh itake, Surface Science, 601, 2007, 3060-3066 - Band bending and band alignment at HfO 2/HfSi xO
S.Yagyu, M.Yoshitake,T.Chikyow: “Determination of Threshold of Photoelectron Yield Spectroscopy (PYS) Using Machine Learning”, Vacuum and Surface, 61(2018), 196-199. Photoelectron emission threshold prediction by photoelectron yield Spectroscopy (PYS) and calculation (simulation) data Monthly corrosion rate of carbon steel in each region
Dec 19, 2020 · Work Function and Band Alignment of Electrode Materials: The Art of Interface Potential for Electronic Devices, Solar Cells, and Batteries (NIMS Monographs) - Kindle edition by Yoshitake, Michiko. Download it once and read it on your Kindle device, PC, phones or tablets.
- Michiko Yoshitake
Dr. Michiko Yoshitake has worked on surfaces and thin films using ultrahigh vacuum instruments for more than 30 years. Her main focus has been the establishment of various prediction methods of either phenomena or material properties rather than the development of materials.
