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

Abstract

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.

Unraveling the dislocation core structure at a van der Waals gap in bismuth telluride

“…This is important since the structure of a dislocation is central to its properties and behavior. For instance, the local elastic strain distribution as well as the specific atomic arrangements in the vicinity of a dislocation core depend on whether the core is compact or dissociated into partial dislocations, which directly impacts the local electronic states and behavior of charge carriers [24,25]. In this paper, we determine the structure of dislocations present at the basal plane of Bi 2 Te 3 , a prototypical tetradymite-structured compound.…”

Theoretical Calculations of Characters and Stability of Glide Dislocations in Zinc Sulfide

“…For instance, Justo et al reported that bond reconstruction at dislocation cores of III-V semiconductors is less stable than that of IV semicondoctors. 30) In the previous report by Kweon et al, 31) it was found that a 90°partial dislocation in CdTe (II-VI semiconductor) tends to have an unreconstructed core energetically more favorably than a reconstructed core. It seems that chemical bonding states of the host crystals may affect detailed atomic structures at their dislocation cores.…”

Spectral Dependence of the Photoplastic Effect in CdZnTe and CdZnTeSe

“…The DFT calculations [ 20 ] show that the cores of several types of dislocation in CdTe may undergo lattice reconstructions along the dislocation lines accompanied with charge modulations resulting in the transformation of the originally metallic character to the semiconducting character of the reconstructed cores.…”