Impurity-Induced Layer Disordering: Current Understanding and Areas for Future Investigation

1989 ◽  
Vol 163 ◽  
Author(s):  
L.J. Guido ◽  
Nick Holonyak
Keyword(s):  
Experimental Data ◽  
Fermi Level ◽  
Impurity Concentration ◽  
Crystal Surface ◽  
Current Understanding ◽  
Experimental Findings ◽  
Level Effect

AbstractThe purpose of this work is to give an overview of the current phenomenological understanding of impurity-induced layer disordering (IILD). First, we identify key experimental findings such as the influence of the crystal surface-ambient interaction, the Fermi-level effect, and the impurity concentration on Al-Ga interdiffusion. Second, we review the strengths and weaknesses of existing IILD models in consideration of the above mentioned experimental data. Finally, we discuss the pitfalls involved in generalizing the results of individual Al-Ga interdiffusion experiments in order to explain a broader collection of IILD data.

scholarly journals A Temperature Variation of Debye-Waller Factor for Alkali and Noble Metals

1983 ◽  
Vol 38 (5) ◽  
pp. 503-508 ◽  
Author(s):  
A. R. Jani ◽  
V. B. Gohel
Keyword(s):  
Experimental Data ◽  
Temperature Variation ◽  
Phenomenological Model ◽  
Noble Metals ◽  
Experimental Information ◽  
Waller Factor ◽  
Critical Examination ◽  
Debye Waller Factor ◽  
Different Temperatures ◽  
Experimental Findings

Debye-Waller factors at different temperatures of four alkali and three noble metals have been computed on the basis of a screened shell phenomenological model. The theoretical values are compared with existing experimental data. Particularly for lithium and potassium, most recent experimental information has been included. A critical examination of the results reveals a satis­factory agreement between the theoretical and experimental findings.

First-principle study of the structural, mechanical, electronic and thermodynamic properties of intermetallic compounds: Pd3M (M=Sc, Y)

2019 ◽  
Vol 33 (27) ◽  
pp. 1950321
Author(s):  
R. Boulechfar ◽  
A. Trad Khodja ◽  
Y. Khenioui ◽  
H. Meradji ◽  
S. Drablia ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Fermi Level ◽  
Debye Model ◽  
Pressure Effects ◽  
Full Potential ◽  
Generalized Gradient ◽  
Text Structures ◽  
Formation Enthalpies ◽  
Densities Of States ◽  
Experimental Findings

The mechanical, electronic and thermodynamic properties of Pd3M (M[Formula: see text]=[Formula: see text]Sc, Y) compounds have been investigated using the Full Potential Linearized Augmented Plane Wave (FP-LAPW) formalism. The generalized gradient approximation (GGA) is used to treat the exchange–correlation terms. The calculated formation enthalpies and the cohesive energies reveal that the L12 structure is more stable than the D0[Formula: see text] one. The obtained lattice parameters and bulk modulus calculations conform well to the available experimental and theoretical results. The elastic and mechanical properties are analyzed and results show that both compounds are ductile in nature. The Debye temperature and melting temperature are also estimated and are in a good agreement with experimental findings. The total and partial densities of states are determined for L12 and D0[Formula: see text] structures. The density of states at the Fermi level, [Formula: see text]([Formula: see text]), indicates electronic stability for both compounds. The presence of the pseudo-gap near the Fermi level is suggestive of formation of directional covalent bonding. The number of bonding electrons per atom [Formula: see text] and the electronic specific heat coefficient [Formula: see text] are also determined. The quasi-harmonic Debye model has been used to explore the temperature and pressure effects on the thermodynamic properties for both compounds.

PHOTOEMISSION CALCULATION WITH A SIMPLE MODEL FOR THE PHOTON FIELD: APPLICATION TO ALUMINIUM

1991 ◽  
Vol 05 (01) ◽  
pp. 65-72 ◽  
Author(s):  
P. DAS ◽  
R.K. THAPA ◽  
N. KAR
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Fermi Level ◽  
Dielectric Function ◽  
Cross Sections ◽  
Free Electron ◽  
Surface Region ◽  
Field Application ◽  
Frequency Dependent ◽  
Photon Field

Photoemission cross-sections are calculated, using a simple “local” dielectric function for computing the photon field in the surface region and free electron wavefunctions. Comparisons are made with the experimental data for the frequency-dependent normal photoemission from the Fermi level of aluminium, and the importance of the variation of the photon field in the surface region is pointed out.

Many Band Effects in Cuprate Superconductors

1997 ◽  
Vol 11 (13) ◽  
pp. 585-592
Author(s):  
S. P. Kruchinin ◽  
A. M. Yaremko ◽  
E. V. Mozdor
Keyword(s):  
Experimental Data ◽  
Fermi Level ◽  
Temperature Dependence ◽  
Theoretical Approach ◽  
Cuprate Superconductors ◽  
Electron Pair ◽  
Recent Experimental Data ◽  
Natural Manner ◽  
System A ◽  
Interacting Electrons

The new theoretical approach is proposed for study the states responsible for superconductivity of crystals. Within the frameworks of worked out approach it is shown that in electron–phonon system a class of new so-called coupled states arises. Postulated in BCS method electron-pair states k1 + k2 = 0, s + s′ = 0 are in natural manner included in this class. The model numerical calculations have shown that SC gap depends on number of bands crossing the Fermi level on the momenta k1+k2 = K≠ 0 of interacting electrons and that the temperature dependence of SC gap for HTSC is more complicated (in agreement with the recent experimental data) then predicted in BCS approach.

THE HOT CARRIER TEMPERATURE IN THE ANALYSIS OF THE FREE TO ACCEPTOR PHOTOLUMINESCENCE TRANSITION

2001 ◽  
Vol 15 (17n19) ◽  
pp. 696-699 ◽  
Author(s):  
G. Fonthal ◽  
M. de los Rios ◽  
J. Quintero ◽  
N. Piraquive ◽  
H. Ariza-Calderón
Keyword(s):  
Fermi Level ◽  
Band Gap ◽  
Density Of States ◽  
Impurity Concentration ◽  
Lattice Temperature ◽  
Band Tail ◽  
Hot Carrier ◽  
Additional Information ◽  
Carrier Temperature ◽  
Shape Equation

We analyzed the free to acceptor (e-A) photoluminescence transition on a GaAs:Ge sample using the hot carrier temperature and the Kane's DOS. This latter temperature was calculated by the spectra largest energy tail. While the lattice temperature was put in the e-A Eagles' shape equation, the fitting was poor but if the modified line was put into the equation, the fitting was better. So, the ionization impurity energy, the band gap, the Fermi level and the band tail can be measured with a better precision than the measurements traditionally made with this method, Additional information about phonons participant can be obtained. In conclusion, the hot carrier temperature and the density of states due to the impurity concentration should be used in the e-A transition photoluminescence analysis.

An Examination of the Mechanisms of Si Diffusion in GaAs

1989 ◽  
Vol 163 ◽  
Author(s):  
Shaofeng Yu ◽  
Ulrich M. Gosele ◽  
Teh Y. Tan
Keyword(s):  
Fermi Level ◽  
Point Defect ◽  
Essential Role ◽  
Defect Concentration ◽  
Experimental Results ◽  
Quantitative Models ◽  
Effect Mechanism ◽  
Level Effect

AbstractAn examination of the three available quantitative models of Si diffusion in GaAs has led to the conclusion that the Fermi-level effect mechanism plays the most essential role. In some experimental results a point defect concentration transient is involved which should be incoorporated in future models.

Vacancy Mediated Diffusion at Surface-Confined Atomic Intermixing

2010 ◽  
Vol 159 ◽  
pp. 121-124 ◽  
Author(s):  
Michail Michailov
Keyword(s):  
Strain Energy ◽  
Crystal Surface ◽  
Adsorbed Layer ◽  
Surface Pattern ◽  
Spontaneous Generation ◽  
Crystal Surfaces ◽  
Adsorbed Atoms ◽  
Atomic Exchange ◽  
Surface Domains ◽  
Experimental Findings

The present study deals with diffusion behavior of adsorbed atoms on stepped crystal surfaces. In volume-immiscible systems, two-dimensional (2D) atomic intermixing at epitaxial interface could be completely blocked on step-free surface domains. This is a result of high diffusion barrier for direct atomic exchange between adsorbed layer and substrate. In that case, diffusion takes place exclusively across the steps of atomic terraces. In such systems, dynamic competition between energy gain by mixing and substrate strain energy results in diffusion scenario where adsorbed atoms form alloyed stripes in the vicinity of terrace edges. At high temperatures, the stripe width increases and finally completely destroys the terraces. This process leads to formation of alloyed 2D atomic islands on top of pure substrate layer. The atomistic Monte Carlo simulations reveal vacancy-mediated mechanism of diffusion inside atomic terraces as a result of spontaneous generation of vacancies at high temperature. Being in agreement with recent experimental findings, the observed surface-confined alloying opens up a way various surface pattern to be configured at different atomic levels on the crystal surface.

Fermi-Level Effect on Group III Atom Interdiffusion in III-V Compounds: Bandgap Heterogeneity and Low Silicon-Doping

1997 ◽  
Vol 490 ◽  
Author(s):  
C.-H. Chen ◽  
U. Gösele ◽  
T. Y. Tan
Keyword(s):  
Fermi Level ◽  
Equilibrium Concentration ◽  
Electric Field Effect ◽  
Silicon Doping ◽  
Group Iii ◽  
Semiconductor Superlattice ◽  
Effect Model ◽  
N Doping ◽  
Short Annealing ◽  
Level Effect

ABSTRACTHeavy n-doping enhanced disordering of GaAs based III-V semiconductor superlattice or quantum well layers, as well as the diffusion of Si in GaAs have been previously explained by the Fermi-level effect model with the triply-negatively-charged group III lattice vacancies identified to be the responsible point defect species. These vacancies have a thermal equilibrium concentration proportional to the cubic power of the electron concentration n, leading to the same dependence of the layer disordering rate. In this paper, in addition, we take into account also the electric field effect produced by the material bandgap heterogeneity and/or hetero-junctions. In heavily n-doped or long time annealing cases, this effect is negligible. At low n-doping levels and for short annealing times, the layer disordering rate can be enhanced or reduced by this effect. Available experimental results of low Si-doped and very short-time annealed samples have been satisfactorily fitted using the Fermi-level effect model.

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