Atomic-Resolution Structure Imaging of Misfit Dislocations at Heterovalent II-VI/III-V Interfaces

The atomically resolved structure of misfit dislocations (MDs) at heterovalent II-VI/III-V (001) compound semiconductor interfaces has been determined using aberration-corrected electron microscopy. The MDs at an ZnTe/InAs interface, which has small lattice mismatch (Delta a/a similar to 0.74%), are primarily 60 degrees glide-set dislocations, with unpaired atomic columns at the dislocation cores mostly containing indium. Lomer dislocations observed at the ZnTe/InP interface (Delta a/a similar to 3.85%) consist of a 10-atom ring and two 5-atom rings, whereas shuffle-set Lomer dislocations observed at the ZnTe/GaAs interface (Delta a/a similar to 7.4%) have symmetrical 5/7-atom ring structures, although asymmetrical and disordered Lomer core structures are sometimes observed. Intensity line profiles across defect-free regions of the heterointerfaces indicate substantial interfacial intermixing. Thus, unpaired atomic columns at the MD cores are likely to consist of mixed atomic species.

Automated summary

The structure of misfit dislocations (MDs) at heterovalent II-VI/III-V (001) compound semiconductor interfaces has been determined using aberration-corrected electron microscopy. The study revealed that MDs at interfaces with different lattice mismatches exhibit different dislocation structures and core compositions, as well as substantial interfacial intermixing.