Polarity control and residual strain in ZnO epilayers grown by molecular beam epitaxy on (0001) GaN/sapphire
Abstract
We report on the polarity control of ZnO grown by plasma assisted molecular beam epitaxy on Ga polar (0001) GaN/sapphire templates simply via the oxygen‐to‐Zn (VI/II) ratio during the growth of a thin nucleation layer at 300 °C. Following Zn pre‐exposure, the ZnO layers nucleated with low VI/II ratios (x formed at the ZnO/GaN interface. A direct correlation between polarity and strain sign of ZnO layers has been found. The Zn‐polar ZnO layers were under tensile biaxial strain, whereas the O‐polar material exhibited compressive strain. Moreover, the amount of residual strain varied linearly with VI/II ratio used during the low‐temperature nucleation layer growth. Strain control with VI/II ratio has been explained by the potential formation of Zn interstitials.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 24, 2016
- Source ID
- 10.1002/pssr.201600189
Entities
People
- Hadis H. Morkoç̌
- Md. Barkat Ullah
- Morteza Monavarian
- Mykyta Toporkov
- Pierre Ruterana
- Saikat Das
- Si Qian Li
- Vitaliy Avrutin
- Ümit Özgür
Organizations
- Air Force Office of Scientific Research
- Virginia Commonwealth University