A Photoemission Investigation of the Interfacial Electronic Properties of Mo and Ni Schottky Barriers to CuInSe2(112)

1992 ◽  
Vol 260 ◽  
Author(s):  
David W. Niles ◽  
Art J. Nelson ◽  
C. Richard Schwerdtfeger ◽  
Hartmut Höchst ◽  
Dennis Rioux
Keyword(s):  
Synchrotron Radiation ◽  
Refractory Metal ◽  
Valence Band Maximum ◽  
Schottky Barriers ◽  
Photoemission Spectroscopy ◽  
Band Maximum ◽  
Ni Alloys ◽  
Ultraviolet Photoemission Spectroscopy ◽  
P Type ◽  
Metal Overlayers

ABSTRACTWe studied Mo and Ni contacts to p-type CuInSe2(112) with angular-resolved synchrotron radiation ultraviolet photoemission spectroscopy in the range 40 eV hv < 120 eV. By varying the photon energy, we determined that emission from the CuInSe2 Г-point in the Brillouin zone occurs for hv = 60 eV, and identified emission from the valence band maximum. After depositing Ni and Mo, we found that the conduction band minimum of the CuInSe2 very nearly aligned to the Fermi edges of both metals, giving Schottky barriers Vsb = 1.05 ±0.1 eV. The interfaces are not atomically abrupt, as seen by the outdiffusion of Se into the refractory metal overlayers and the formation of In-Mo and In-Ni alloys.

Photoemission Study of the α-Sn/Cdte(110) Interface Growth

1987 ◽  
Vol 94 ◽  
Author(s):  
Ming Tang ◽  
David W. Niles ◽  
Isaac Hernández-Calderón ◽  
Hartmut Hóchst
Keyword(s):  
Synchrotron Radiation ◽  
Fermi Level ◽  
Valence Band ◽  
Valence Band Maximum ◽  
Photoemission Spectroscopy ◽  
Mbe Growth ◽  
Band Maximum ◽  
Interface Growth ◽  
Interfacial Growth ◽  
Photoemission Study

ABSTRACTAngular Resolved Photoemission Spectroscopy with Synchrotron radiation has been used to study the MBE growth of α-Sn on CdTe(110). Sn grows epitaxially and the Fermi level pins at 0.72eV above the CdTe valence band maximum. Outdiffusion or segregation of Cd in the α-Sn layer is not observed. For small Sn coverages the Sn4d core spectra show a second component which may be due to the initial interfacial growth of SnTe.

Photoemission Studies of the Ag/InP(110) Interface: Interfacial Reactions and Schottky Barrier Formation

1983 ◽  
Vol 25 ◽  
Author(s):  
W. G. Petro ◽  
T. Kendelewicz ◽  
I. A. Babalola ◽  
I. Lindau ◽  
W. E. Spicer
Keyword(s):  
Valence Band Maximum ◽  
Interfacial Reactions ◽  
Core Level ◽  
Photoemission Spectroscopy ◽  
Band Bending ◽  
X Ray ◽  
Barrier Formation ◽  
Deconvolution Technique ◽  
P Type ◽  
Measurable Change

ABSTRACTRoom-temperature interfacial reactions at the Ag/InP (110) interface have been studied using soft x-ray photoemission spectroscopy of the In 4d and P 2p core levels. For low Ag coverages (less than 1 monolayer (ML)) no measurable change in core level shapes is observed, and the shift in core level position is due solely to band bending. At high Ag coverages (up to 72 ML) we observe dissociated In metal, P atoms near the surface, and Ag clustering. Fermi level movement is deduced from these spectra using a deconvolution technique, and pinning positions of 0.40 ± 0.05 eV below the conduction-band minimum for n-type and 0.5 ± 0.l eV above the valence-band maximum for p-type are found. These positions are in close agreement with calculations of native defect levels.

THE ADSORPTION AND DESORPTION OF OXYGEN ON CdZnTe (111)B-(2 × 2) SURFACE

2013 ◽  
Vol 20 (03n04) ◽  
pp. 1320001
Author(s):  
XUXU BAI ◽  
WANQI JIE ◽  
GANGQIANG ZHA ◽  
WENHUA ZHANG ◽  
JUNFA ZHU ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Photoelectron Spectroscopy ◽  
Oxygen Adsorption ◽  
Photoemission Spectroscopy ◽  
Adsorption And Desorption ◽  
X Ray ◽  
Oxygen Exposure ◽  
Surface Work ◽  
Ultraviolet Photoemission Spectroscopy ◽  
Surface Work Function

The oxygen adsorption and desorption on the CdZnTe (111) B -(2×2) surface were studied with synchrotron radiation ultraviolet photoemission spectroscopy (SRUPS) and X-ray photoelectron spectroscopy (XPS). The results show that a surface state of clean CdZnTe (111) B -(2×2) surface appears at 0.5 eV below Fermi level ( E F), which disappears after the oxygen exposure, and shows again after annealing in UHV. The surface work function of CdZnTe (111) B -(2×2) decreases after the oxygen exposure, and futher reduces after annealing.

scholarly journals Machine Learning Chemical Guidelines for Engineering Electronic Structures in Half-Heusler Thermoelectric Materials

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Maxwell T. Dylla ◽  
Alexander Dunn ◽  
Shashwat Anand ◽  
Anubhav Jain ◽  
G. Jeffrey Snyder
Keyword(s):  
Machine Learning ◽  
Valence Band ◽  
Electronic Structures ◽  
Electronic Band Structure ◽  
Valence Band Maximum ◽  
Electronic Band ◽  
Band Maximum ◽  
Orbital Phase ◽  
Valence Bands ◽  
P Type

Half-Heusler materials are strong candidates for thermoelectric applications due to their high weighted mobilities and power factors, which is known to be correlated to valley degeneracy in the electronic band structure. However, there are over 50 known semiconducting half-Heusler phases, and it is not clear how the chemical composition affects the electronic structure. While all the n-type electronic structures have their conduction band minimum at either the Γ- or X-point, there is more diversity in the p-type electronic structures, and the valence band maximum can be at either the Γ-, L-, or W-point. Here, we use high throughput computation and machine learning to compare the valence bands of known half-Heusler compounds and discover new chemical guidelines for promoting the highly degenerate W-point to the valence band maximum. We do this by constructing an “orbital phase diagram” to cluster the variety of electronic structures expressed by these phases into groups, based on the atomic orbitals that contribute most to their valence bands. Then, with the aid of machine learning, we develop new chemical rules that predict the location of the valence band maximum in each of the phases. These rules can be used to engineer band structures with band convergence and high valley degeneracy.

Co-doping of magnesium with indium in nitrides: first principle calculation and experiment

RSC Advances ◽  
2016 ◽  
Vol 6 (6) ◽  
pp. 5111-5115 ◽  
Author(s):  
Zhiqiang Liu ◽  
Binglei Fu ◽  
Xiaoyan Yi ◽  
Guodong Yuan ◽  
Junxi Wang ◽  
...  
Keyword(s):  
Valence Band ◽  
Valence Band Maximum ◽  
First Principle ◽  
Principle Calculation ◽  
First Principle Calculation ◽  
Band Maximum ◽  
Co Doping ◽  
P Type

The valence band maximum could be modified by specific states coupling, thus improving the p-type dopability in In–Mg co-doping GaN.

First-Principles Investigation on Ag, N Codoped in p-Type ZnO

2012 ◽  
Vol 724 ◽  
pp. 115-118
Author(s):  
Cheng He ◽  
Wen Xue Zhang ◽  
Li Duan ◽  
Qing Wei Li ◽  
Zhong Qi Shi
Keyword(s):  
Band Structure ◽  
First Principles ◽  
Valence Band Maximum ◽  
Density Of State ◽  
Defect States ◽  
Generalized Gradient ◽  
Band Maximum ◽  
Generalized Gradient Approximation ◽  
Calculation Results ◽  
P Type

The geometric structure, band structure and density of state of pure and Ag-N, Ag-2N codoped wurtzite ZnO have been investigated by first-principles ultrasoft pseudopotential method in the generalized gradient approximation. These structures induce fully occupied defect states above the valence-band maximum of bulk ZnO. The calculation results show that the codoped structure Ag-N has better stability. Meanwhile, the carrier concentration is increased in the Ag-2N codoped configuration where the delocalized features are obvious. Our findings suggest that codoping of Ag-2N could efficiently enhance the N dopant solubility and is likely to yield better p-type conductivity.

Defect formation of CuI-doped by group-IIB elements

2019 ◽  
Vol 33 (01) ◽  
pp. 1850423
Author(s):  
Hui Chen ◽  
Mu Gu
Keyword(s):  
First Principles ◽  
Formation Energy ◽  
Defect Formation ◽  
Valence Band Maximum ◽  
Acceptor Level ◽  
First Principles Calculations ◽  
Transition Energies ◽  
Band Maximum ◽  
P Type ◽  
Formation Energies

First-principles calculations have been performed to investigate the doping defects in CuI with group-IIB elements such as Zn, Cd and Hg. The calculated transition energies for substitutional Zn, Cd and Hg are 1.32, 1.28 and 0.60 eV, respectively. These group-IIB elements at the substitutional sites complex with a copper vacancy [Formula: see text] have the lower formation energies as compared to dopants located at the substitutional sites or interstitial sites, respectively. Among all the complex defects considered, [Formula: see text] has the lowest formation energy and it induces the acceptor level [Formula: see text] eV above the valence-band maximum (VBM), which is close to the acceptor level [Formula: see text] eV of [Formula: see text], suggesting that Hg may be a good dopant for CuI to improve its p-type conductivity.

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