Yujeong Lee
Research Subjects
Yujeong Lee has a total of 2 co-authors. Here are the top co-authors by number of shared publications:
- Daseob Yoon
Department of Electrical Engineering, Display and Semiconductor Engineering, Pukyong National University, Busan, 48513, Republic of Korea
1 shared publication - Junwoo Son
Seoul National University
1 shared publication
Latest Publications
- Open Access
- 23 April 2026
- Published by Elsevier in SSRN Electronic Journal
Controlling Sr Volatilization for Atomically Flat Step-Terrace SrTiO3 Surface via H2O-Assisted Thermal Annealing
Atomically flat SrTiO3 (001) surfaces with well-defined step-terrace structures are essential for high-quality oxide heterostructures, but their high-temperature evolution is strongly affected by surface segregation and defect formation. Here, we investigated SrTiO3 (001) surfaces annealed at 1200 °C in dry-air, Ar, and humid-air using atomic force microscopy and thermodynamic analysis. Dry-air annealing initially promoted step formation, but prolonged annealing induced phase inhomogeneity, indicating the formation of a thermodynamically stable SrO-rich surface layer. Ar annealing did not suppress this problem and instead produced a disordered surface, likely due to oxygen-vacancy-related instability. In contrast, humid-air annealing delayed SrO segregation by increasing the volatility of excess Sr species through hydroxide formation, enabling a well-defined step-terrace structure within an intermediate annealing window. However, SrO segregation reappeared after extended humid annealing, showing that humidity provides kinetic suppression rather than thermodynamic elimination. These results suggest that precise control of atmosphere chemistry can serve as a general strategy for balancing surface segregation and volatility-driven cation removal in complex oxide substrate preparation.
- 23 April 2026
- Published by Elsevier in SSRN Electronic Journal
Open AccessControlling Sr Volatilization for Atomically Flat Step-Terrace SrTiO3 Surface via H2O-Assisted Thermal Annealing
Atomically flat SrTiO3 (001) surfaces with well-defined step-terrace structures are essential for high-quality oxide heterostructures, but their high-temperature evolution is strongly affected by surface segregation and defect formation. Here, we investigated SrTiO3 (001) surfaces annealed at 1200 °C in dry-air, Ar, and humid-air using atomic force microscopy and thermodynamic analysis. Dry-air annealing initially promoted step formation, but prolonged annealing induced phase inhomogeneity, indicating the formation of a thermodynamically stable SrO-rich surface layer. Ar annealing did not suppress this problem and instead produced a disordered surface, likely due to oxygen-vacancy-related instability. In contrast, humid-air annealing delayed SrO segregation by increasing the volatility of excess Sr species through hydroxide formation, enabling a well-defined step-terrace structure within an intermediate annealing window. However, SrO segregation reappeared after extended humid annealing, showing that humidity provides kinetic suppression rather than thermodynamic elimination. These results suggest that precise control of atmosphere chemistry can serve as a general strategy for balancing surface segregation and volatility-driven cation removal in complex oxide substrate preparation.