In Situ Thermal Preparation by CO$_2$-Laser and Chemical Characterization of Oxide Substrates Across Multiple Crystallographic Orientations
Year: 2026
Type: preprint
Abstract: Atomically flat and chemically controlled oxide substrate surfaces are essential for high-quality epitaxial growth of complex materials and heterostructures. Previous studies have demonstrated in situ thermal preparation of selected oxide substrates, primarily focusing on conventional low-index orientations such as SrTiO$_3$ (100) and LaAlO$_3$ (100). Here, we extend these methodologies to a broader range of oxide substrates and crystallographic orientations, including challenging polar surfaces. We present a systematic study of the in situ thermal preparation of SrTiO$_3$ (100), SrTiO$_3$ (111), GdScO$_3$ (110), LaAlO$_3$ (111), (LaAlO$_3$)$_{0.3}$(Sr$_2$AlTaO$_6$)$_{0.7}$ (001), and NdGaO$_3$ (110) single crystal substrates. The substrates are annealed in a vacuum chamber under a controlled oxygen background environment using a CO$_2$ laser heating system. The optimized annealing conditions produce atomically flat step-and-terrace structures, long-range surface crystallinity, and effectively clean surfaces across all the investigated substrates. Our results establish a versatile, reproducible, and broadly applicable platform for the in situ preparation of oxide substrates immediately prior to epitaxial growth. These results also provide practical guidelines for interface engineering and surface-sensitive investigations of complex materials.
Source: arXiv (Cornell University)
Institutions: Louisiana State University, University of Johannesburg
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funder: Louisiana State University
OpenAlex ID: W7223144752