Interface and defect structures in ZnO films on m-plane sapphire substrates

• Published in: Journal of crystal growth Vol. 312; no. 2; pp. 238 - 244
• Main Authors: Lee, Jae Wook, Kim, Jung-Hyun, Han, Seok Kyu, Hong, Soon-Ku, Lee, Jeong Yong, Hong, Sun Ig, Yao, Takafumi
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 2010; Elsevier
• Subjects: A1. Characterization; A1. Defects; A1. Interfaces; A3. Molecular beam epitaxy; B1. Zinc compounds; B2. Semiconducting II–VI materials; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Exact sciences and technology; Linear defects: dislocations, disclinations; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Physics; Stacking faults and other planar or extended defects; Structure of solids and liquids; crystallography; 68.37.Lp; 78.66.Hf; 68.35.Ct; A3. Molecular beam epitaxy; B2. Semiconducting II–VI materials; A1. Characterization; A1. Interfaces; B1. Zinc compounds; 61.72.Ff; 61.72.Nn; A1. Defects; Misfit dislocations; Plasma assisted processing; Burgers vector; Thin films; Interface structure; Molecular beam epitaxy; Zinc oxide; B2. Semiconducting II-VI materials; Defect structure; Aluminium oxide; Stacking faults; Interfaces; Zinc compounds; Transmission electron microscopy; II-VI semiconductors; Anisotropy
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2009.10.023

Interface and defect structures in ZnO films grown on ( 1 0 1 ¯ 0 ) m-plane sapphire substrates by plasma-assisted molecular beam epitaxy were investigated by transmission electron microscopy (TEM). Distribution of misfit dislocations (MDs) at the ZnO/Al 2O 3 interfaces was orientation dependent and quite anisotropic. In addition, type-І 1 stacking faults (SFs) bounded by the Frank dislocations with the Burgers vector of 1 / 6 [ 2 0 2 ¯ 3 ] were observed to be predominant. Many SFs initiated from the interface to the film surface were observed in addition to the MDs at the interface. The analysis of the high-resolution TEM revealed no correlation between the SFs and the MDs. The ZnO films were not found to be pure m-plane ZnO and ( 1 0 1 ¯ 3 ) domains were frequently observed in the film with otherwise mostly ( 1 0 1 ¯ 0 ) m-plane in nature. These ( 1 0 1 ¯ 3 ) domains were not nucleated at the interface but initiated inside the ZnO film above the interface and reached the top surface.