Reduction of threading dislocations in ZnO/(0001) sapphire film heterostructure by epitaxial lateral overgrowth of nanorods

被引：23

作者：

Sun, Yuekui ^{[1
]}

Cherns, David ^{[1
]}

Doherty, Rachel P. ^{[2
]}

Warren, James L. ^{[2
]}

Heard, Peter J. ^{[3
]}

机构：

[1] Univ Bristol, HH Wills Phys Lab, Bristol BS8 1TL, Avon, England

[2] Univ Bristol, Sch Chem, Bristol BS8 1TS, Avon, England

[3] Univ Bristol, Interface Anal Ctr, Bristol BS2 8BS, Avon, England

来源：

JOURNAL OF APPLIED PHYSICS | 2008年 / 104卷 / 02期

关键词：

D O I：

10.1063/1.2957082

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Transmission electron microscopy was used to study threading dislocations (TDs) in epitaxial ZnO films on (0001) sapphire substrates produced by a two-step method. First, ZnO was deposited by pulsed laser deposition. It was found that the sample consisted of a continuous buffer layer with a high density, /7x10(10)cm(2), of TDs, with c-aligned nanorods on its top. The nanorods revealed few, if any, TDs. A further layer of ZnO was then grown under conditions favoring nanorod growth, using either chemical vapor deposition (CVD) or a hydrothermal method. In both cases the nanorods grew laterally and eventually coalesced to form a continuous overgrowth. The nanorods remained mostly free of dislocations until coalescence. New grain boundary dislocations were generated where nanorods coalesced, but many of these dislocations migrated laterally and interacted with other dislocations to form closed loops. The TD density at the top of the continuous film was thereby reduced to 1x10(9)/cm(2) and 7x10(9)/cm(2) in the cases of hydrothermal and CVD treatments, respectively. The mechanism of growth and the means by which TDs are reduced are explained. (C) 2008 American Institute of Physics.

引用

页数：7