B23-P-17Microstructural Analysis of Lithiated Sn/Sn Interface in Gelatin-Coated Sn Particle

Abstract

LSAT:(La0.3Sr0.7)( Al0.65Ta0.35)O3 is one of the most preferable substrates for GaN thin film growth. However, there reported a few studies concerning the surface structures of LSAT substrate. In this study, we investigated annealing conditions for constructing surface step-terrace structure and directly observed the surface structure mainly by Z-contrast imaging. Commercially available LSAT (001) substrates were annealed at 800°C~1300°C for 0.5h~5h in air and Ar-5%H2. After annealing, the surface structures were analyzed by SEM, AFM, TEM and STEM. As results, the surface structure was found to depend on the annealing conditions. Precipitates were formed at the surface annealed at 1300°C irrespective of oxygen partial pressure. The amount of the precipitates was largely decreased by lowering annealing temperature. The surface smoothness at lower annealing temperature varies by oxygen partial pressure. The surface is atomically rough in air while the surface is atomically flat to form step-terrace structure in Ar-5%H2. Figure shows an example of the obtained step-terrace structure. The step height is a unit cell length of LSAT and the terraces are terminated at B-sites. The surface structure change due to the variation of annealing conditions will be presented. HAADF STEM image of step-terrace structure. B23-P-17 doi:10.1093/jmicro/dfv291 Microstructural Analysis of Lithiated Sn/Sn Interface in Gelatin-Coated Sn Particle