Structure of the Basal Edge Dislocation in ZnO

Atsutomo Nakamura,Yuichi Ikuhara,Eita Tochigi,Katsuyuki Matsunaga,Yu Oshima,Tatsuya Yokoi,Yuho Furushima,Ryota Nagahara

doi:10.3390/cryst8030127

Atsutomo Nakamura, Yuichi Ikuhara + Show 6 more

Open Access

https://doi.org/10.3390/cryst8030127

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Abstract

Basal dislocations having a Burgers vector of 1/3<2 1 ¯ 1 ¯ 0> in zinc oxide (ZnO) with the wurtzite structure are known to strongly affect physical properties in bulk. However, the core structure of the basal dislocation remains unclear. In the present study, ZnO bicrystals with a {2 1 ¯ 1 ¯ 0}/<01 1 ¯ 0> 2° low-angle tilt grain boundary were fabricated by diffusion bonding. The resultant dislocation core structure was observed by using scanning transmission electron microscopy (STEM) at an atomic resolution. It was found that a basal edge dislocation in α-type is dissociated into two partial dislocations on the (0001) plane with a separation distance of 1.5 nm, indicating the glide dissociation. The Burgers vectors of the two partial dislocations were 1/3<1 1 ¯ 00> and 1/3<10 1 ¯ 0>, and the stacking fault between the two partials on the (0001) plane has a formation energy of 0.14 J/m2. Although the bicrystals have a boundary plane of {2 1 ¯ 1 ¯ 0}, the boundary basal dislocations do not exhibit dissociation along the boundary plane, but along the (0001) plane perpendicular to the boundary plane. From DFT calculations, the stacking fault on the (0001) plane was found to be much more stable than that on {2 1 ¯ 1 ¯ 0}. Such an extremely low energy of the (0001) stacking fault can realize transverse dissociation of the basal dislocation of ZnO.

Highlights

The wurtzite structure is a stable crystal structure for binary compound semiconducting materials such as GaN, AlN, CdS, zinc oxide (ZnO), and so on
We focus on the core structure of the basal edge dislocation in wurtzite
ZnO were evaluated by density functional theory (DFT) calculations to understand the origin of the observed atomic structure of the basal edge dislocation

Summary

Introduction

The wurtzite structure is a stable crystal structure for binary compound semiconducting materials such as GaN, AlN, CdS, ZnO, and so on. The bicrystal experiment has proven to be an efficient method for evaluating atomic consists of periodically arranged edge dislocations, which have a Burgers vector perpendicular to the structures and properties of dislocations [14,15,16,17]. This is because a low-angle tilt grain boundary boundary plane. ZnO were evaluated by density functional theory (DFT) calculations to understand the origin of the observed atomic structure of the basal edge dislocation

Experimental

Schematics andand optical micrograph

DFT Calculations

Results and Discussion

Conclusions