Journal ArticleRevealing a Pathway for Low‐Temperature Recrystallization in GermaniumVelişa, Gihan [Horia Hulubei National Institute for Physics and Nuclear Engineering IF Măgurele 077125 Romania] (ORCID:0000000344210790); Zarkadoula, Eva [Center for Nanophase Materials Sciences Oak Ridge National Laboratory Oak Ridge TN 37831 USA] (ORCID:0000000268869664); Iancu, Decebal [Horia Hulubei National Institute for Physics and Nuclear Engineering IF Măgurele 077125 Romania] (ORCID:0000000210071799); Mihai, Maria D [Horia Hulubei National Institute for Physics and Nuclear Engineering IF Măgurele 077125 Romania] (ORCID:0000000222891997); Boulle, Alexandre [Institut de Recherche sur les Céramiques CNRS UMR 7315 Limoges 87068 France] (ORCID:0000000310426403); Tong, Yang [Institute for Advanced Studies in Precision Materials Yantai University Yantai Shandong 264005 China] (ORCID:0009000231317273); Chen, Da [School of Energy and Environment Southeast University Nanjing 211189 China] (ORCID:0000000231254033); Zhang, Yanwen [Department of Mechanical and Materials Engineering Queen's University Kingston Ontario K7L2N8 Canada] (ORCID:0000000318333885); Weber, William J [Department of Materials Science &amp; Engineering University of Tennessee Knoxville TN 37996 USA] (ORCID:0000000290177365)<title>Abstract</title> <p>Thermally activated annealing in semiconductors faces inherent limitations, such as dopant diffusion. Here, a nonthermal pathway is demonstrated for a complete structural restoration in predamaged germanium via ionization‐induced recovery. By combining experiments and modeling, this study reveals that the energy transfer of only 2.4 keV nm⁻¹from incident ions to target electrons can effectively annihilate pre‐existing defects and restore the original crystalline structure at room temperature. Moreover, it is revealed that the irradiation‐induced crystalline‐to‐amorphous (c/a) transformation in Ge is reversible, a phenomenon previously considered unattainable without additional thermal energy imposed during irradiation. For partially damaged Ge, the overall damage fraction decreases exponentially with increasing fluence. Surprisingly, the recovery process in preamorphized Ge starts with defect recovery outside the amorphous layer and a shrinkage of the amorphous thickness. After this initial stage, the remaining damage decreases slowly with increasing fluence, but full restoration of the pristine state is not achieved. These differences in recovery are interpreted in the framework of structural differences in the initial defective layers that affect recovery kinetics. This study provides new insights on reversing the c/a transformation in Ge using highly‐ionizing irradiation and has broad implications across materials science, radiation damage mitigation, and fabrication of Ge‐based devices.</p>Wiley-VCH GmbH2025-11-0110646283Advanced Science1241e076302198-3844https://doi.org/10.1002/advs.2025076302104228athermal recoverycomplete damage annealingdefect analysesdefects simulationgermaniumNational Science Foundation