Structure and energy of the partial dislocation cores in GaAs

Beckman, Scott P.; Chrzan, D. C.

doi:10.1002/pssb.200666808

Cited by 8 publications

(10 citation statements)

References 42 publications

(45 reference statements)

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“…11(c) reveals that the Cd A1 -Cd B1 bonding state, which lies in the middle of the band gap, is fully occupied by the donated charge (1.0e) from the sp 2 -like Cd A2 and Cd B2 . We point out that our calculated DP structure is quite different from the suggested DP structures in group-IV and III-V semiconductors; 21,23 in CdTe, the DP structure we find is 0.44 eV/nm lower in energy than the structure analogous to that found in group-IV and III-V semiconductors. 38 Such distinct DP structure for the Cd-core 90…”

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confidence: 50%

“…The directionality of broken bonds that form the dislocation core lies in the plane perpendicular to the line direction for the shuffle set (on the {110} plane), so that reconstructions occur in that plane rather than along the dislocation line; for the glide set, the broken bonds lie nearly on the {111} slip planes and many are oriented such that reconstructions along the dislocation line may be favored. [19][20][21][22][23] For each isolated 60…”

Section: Introductionmentioning

confidence: 99%

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First-principles study of atomic and electronic structures of60∘perfect and30∘/90∘partial glide dislocations in CdTe

2016

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The atomic and electronic structures of 60• glide perfect and 30• /90• glide partial dislocations in CdTe are studied using combined semi-empirical and density functional theory calculations. The calculations predict that the dislocation cores tend to undergo significant reconstructions along the dislocation lines from the singly-periodic (SP) structures, yielding either doubly-periodic (DP) ordering by forming a dimer or quadruplyperiodic (QP) ordering by alternating a dimer and a missing dimer. Charge modulation along the dislocation line, accompanied by the QP reconstruction for the Cd-/Te-core 60• perfect and 30• partials or the DP reconstruction for the Cd-core 90• partial, results in semiconducting character, as opposed to the metallic character of the SP dislocation cores. Dislocation-induced defect states for the 60• Cd-/Te-core are located relatively close to the band edges, whereas the defect states lie in the middle of the band gap for the 30• Cd-/Te-core partial dislocations. In addition to the intra-core charge modulation within each QP core, the possibility of inter-core charge transfer between two different dislocation cores when they are paired together in the same system is discussed. The analysis of the electronic structures reveals the potential role of the dislocations on charge transport in CdTe, particularly in terms of charge trapping and recombination.

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confidence: 50%

Section: Introductionmentioning

confidence: 99%

First-principles study of atomic and electronic structures of60∘perfect and30∘/90∘partial glide dislocations in CdTe

2016

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“…Although previous studies only considered neutral dislocations in GaAs, 15,20,24,26 their stability depends on the charge state as shown in Si. 39 For the neutral 90°α, as discussed earlier, the residual electrons occupying the antibonding dimer states are responsible for the enhanced relative stability of SP.…”

Section: Discussionmentioning

confidence: 99%

“…[17][18][19] All possible structural permutations for glissile o1104 dislocations in a III-V crystal are illustrated by the dislocation loop shown in Figure 1. 20 Dissociation into partial dislocations creates two partial dislocation loops separated by a stacking fault. The angle between the partial Burgers vectors (dashed arrows) and the line direction for all segments is either 30°or 90°, and the vector sum of the partial dislocation pairs always equals the Burgers vector of the full dislocation (solid arrow).…”

Section: Introductionmentioning

confidence: 99%

“…There are two well-established reconstructions with similar formation energies, referred to as 'single period' (SP) and 'double period' (DP) based on their periodicity along the dislocation line. [20][21][22][23][24][25] A 30°partial dislocation reconstructs with dimers aligned parallel to the dislocation line direction. 20,24,26 An atomic model for each of these reconstructions is shown in Figure 2.…”

Section: Introductionmentioning

confidence: 99%

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Period-doubling reconstructions of semiconductor partial dislocations

et al. 2015

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Atomic-scale understanding and control of dislocation cores is of great technological importance, because they act as recombination centers for charge carriers in optoelectronic devices. Using hybrid density-functional calculations, we present period-doubling reconstructions of a 90°partial dislocation in GaAs, for which the periodicity of like-atom dimers along the dislocation line varies from one to two, to four dimers. The electronic properties of a dislocation change drastically with each period doubling. The dimers in the single-period dislocation are able to interact, to form a dispersive one-dimensional band with deep-gap states. However, the inter-dimer interaction for the double-period dislocation becomes significantly reduced; hence, it is free of mid-gap states. The Ga core undergoes a further period-doubling transition to a quadruple-period reconstruction induced by the formation of small hole polarons. The competition between these dislocation phases suggests a new passivation strategy via population manipulation of the detrimental single-period phase.

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Applicability of molecular statics simulation to partial dislocations in GaAs

Riedl

Lindner

2020

Solid State Communications

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The suitability of molecular statics (MS) simulations to model the structure of 90° glide set partial dislocation cores in GaAs is analyzed. In the MS simulations the atomic positions are iteratively relaxed by energy minimization, for which a Tersoff potential parametrization appropriate for nanostructures has been used. We show that for the Ga terminated partial the resulting bond lengths of the atoms in the dislocation core agree within 5-10% with those of previous density functional theory studies, whereas a significant discrepancy appears in the case of the As terminated partial.

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Structure and energy of the partial dislocation cores in GaAs

Cited by 8 publications

References 42 publications

First-principles study of atomic and electronic structures of60∘perfect and30∘/90∘partial glide dislocations in CdTe

First-principles study of atomic and electronic structures of60∘perfect and30∘/90∘partial glide dislocations in CdTe

Period-doubling reconstructions of semiconductor partial dislocations

Applicability of molecular statics simulation to partial dislocations in GaAs

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