Real-Time Observation of Temperature-Induced Surface Nanofaceting in M-Plane α-Al2O3

The spontaneous crystal surface reconstruction of M-plane Al₂O₃ is employed for nanopatterning and nanofabrication in various fields of research including, among others, magnetism, superconductivity, and optoelectronics. However, investigating this reconstruction process from a planar surface to one with a nanoscale ripple topography is challenging, since it occurs at high temperatures above approximately 1000 °C. This contribution presents an approach combining ex-situ Atomic Force Microscopy with in-situ and simulated Grazing Incidence Small Angle X-ray Scattering to further elucidate this morphological transition. It provides time-resolved information on all relevant morphological characteristics required to trace the surface topography during recon-
struction and thereby offers a comprehensive picture of this process on a nanometer scale.