Bounds on the range of density-functional-theory point-defect levels in semiconductors and insulators

Modine, Normand A.; Wright, Alan F.; Lee, Stephen Roger

doi:10.1016/j.commatsci.2014.05.032

Cited by 15 publications

(19 citation statements)

References 42 publications

(71 reference statements)

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“…This agreement is simply a fortuitous result of higher band filling for small supercells. Such agreement tends to persist at small supercells sizes (~32-216 atoms) for the bounds calculated for a variety of semiconductors, explaining why semilocal DFT finds levels that span the experimental gap [14].…”

Section: E Calculation Of Bounds On Defect Transition Levelsmentioning

confidence: 99%

“…As the supercell size approaches infinity and band filling decreases, we see the bounds approach the Kohn-Sham band edges [14].…”

Section: E Calculation Of Bounds On Defect Transition Levelsmentioning

confidence: 99%

“…We proceed using a recently developed approach where defect levels are compared to thermodynamically derived bounds on the defect levels, with the bounds defined as follows [14]: For a defect supercell of size L, the upper bound is the energy to add one electron to a bulk supercell of size L,…”

Section: E Calculation Of Bounds On Defect Transition Levelsmentioning

confidence: 99%

“…This section also briefly summarizes our recently developed bounds-analysis approach [14,15], which we will apply in Section III to assess the validity, within the framework of the DFT calculations, of proposed charge states and defect structures found to be stable by the calculations. Section III reports and discusses our computational results for As interstitials in In 0.5 Ga 0.5 As.…”

Section: Introductionmentioning

confidence: 99%

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First-principles survey of the structure, formation energies, and transition levels of As-interstitial defects in InGaAs

et al. 2015

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While point defects in elemental (Si) and compound (GaAs, GaN, AlN) semiconductors have been extensively studied both experimentally and theoretically, only limited theoretical studies of these defects exist for technologically important binary (Si x Ge 1-x ) and pseudo-binary (In x Ga 1-x As, In x Ga 1-x N, Al x Ga 1-x N) semiconductor alloys. Here, we use density-functional theory (DFT) and a recently developed boundsanalysis approach to survey the atomic structures, formation energies, and charge-state transition levels of the stable and metastable states of As interstitials in the pseudo-binary alloy In 0.5 Ga 0.5 As. Our studies consider seven different candidate defect structures for the As interstitial, with calculations performed for selected defect charge states in the range q=-2 to q=+3. In each case, the mean and standard deviation of the defect formation energy are determined using statistical sampling methods that place the defect into a wide variety of differing local-alloy environments. When examined from the point of view of the mean formation energy of the defect, the stable configurations of the As interstitial in In 0.5 Ga 0.5 As are found to resemble previous findings for GaAs, with a C 1h -p001 III interstitial structure in a q=+1 charge state favored near mid-gap and below, and a C 2v -110 a split-interstitial structure in a q=-1 charge state favored above mid-gap (the named point-group symmetries refer to the underlying symmetry that the alloy defect would possess if within GaAs). The statistical sampling reveals a strong dependence of the defect formation energy on the local alloy environment, with the standard deviation, σ, of the formation energy approaching 0.21 eV for the most stable As-interstitial structures. Because the range of ground-state 2 energies encountered by an As interstitial defect when moving through the alloy is found to be quite large, approaching ~ 1.2 eV (±3σ), defect-diffusion pathways in In 0.5 Ga 0.5 As will have spatial and temporal complexities not found in GaAs. ________________________ a) Electronic mail: srlee@sandia.gov 3

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Section: E Calculation Of Bounds On Defect Transition Levelsmentioning

confidence: 99%

“…As the supercell size approaches infinity and band filling decreases, we see the bounds approach the Kohn-Sham band edges [14].…”

Section: E Calculation Of Bounds On Defect Transition Levelsmentioning

confidence: 99%

Section: E Calculation Of Bounds On Defect Transition Levelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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First-principles survey of the structure, formation energies, and transition levels of As-interstitial defects in InGaAs

et al. 2015

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“…Then, the simulation time is increased accordingly to the selected event frequency. KMC models make use of a large number of parameters which are usually extracted from experiments or more fundamental simulation techniques, such as classical molecular dynamics (CMD) [29,30] or ab-initio methods [31,32].…”

Section: Introductionmentioning

confidence: 99%

Improved physical models for advanced silicon device processing

Pelaz

Marqués

Aboy

et al. 2017

Materials Science in Semiconductor Processing

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We review atomistic modeling approaches for issues related to ion implantation and annealing in advanced device processing. We describe how models have been upgraded to capture physical mechanisms in more detail as a response to the accuracy demanded in modern process and device modeling. Implantation and damage models based on the binary collision approximation have been improved to describe the direct formation of amorphous pockets for heavy or molecular ions. The use of amorphizing implants followed by solid phase epitaxial regrowth has motivated the development of detailed models that account for amorphization and recrystallization, considering the influence of crystal orientation and stress conditions. We apply simulations to describe the role of implant parameters to minimize residual damage, and we address doping issues that arise in non-planar structures such as FinFETs.

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Electronic structure of threading dislocations in wurtzite GaN

Belabbas

Chen

Nouet

2015

Phys. Status Solidi C

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We have carried out atomistic simulations, based on density functional theory, to investigate the atomic and electronic structures of the three types of prismatic threading dislocations in hexagonal gallium nitride. Screw and mixed threading dislocations were demonstrated to introduce both deep and shallow gap states, while most of core configurations of the edge dislocation introduce solely shallow states. The higher electrical activity of both screw and mixed dislocations, compared to the edge one, is correlated with the high dispersion of their energy levels, within the GaN bandgap. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Bounds on the range of density-functional-theory point-defect levels in semiconductors and insulators

Cited by 15 publications

References 42 publications

First-principles survey of the structure, formation energies, and transition levels of As-interstitial defects in InGaAs

First-principles survey of the structure, formation energies, and transition levels of As-interstitial defects in InGaAs

Improved physical models for advanced silicon device processing

Electronic structure of threading dislocations in wurtzite GaN

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