Germanium displays enhanced carrier mobility under mechanical straining, which makes it an important material for optoelectronics and ultrafast semiconductor devices. However, it is extremely brittle at ambient temperature. Here, we demonstrate plasticity in single-crystalline Ge over a wide temperature range, even at cryogenic temperatures, by using in situ compression of micron-sized specimens. Micromechanical tests were performed from −100°C to 400°C, which spans a homologous temperature range of 0.14–0.56 T_m for Ge. This wide temperature range includes two transitions in dislocation-mediated plastic deformation: the shuffle-to-glide (∼0.31 T_m) and brittle-to-ductile (∼0.47 T_m) transitions. Size effect in Ge is weak for deformation via partial dislocations but more pronounced via perfect dislocations. This study provides comprehensive knowledge for the fundamental understanding of temperature- and size-dependent plasticity and associated defect behavior in covalent semiconductors and practical guidelines for fabrication of robust Ge-based micro-structures for device applications.

锗在机械应变下表现出增强的载流子迁移率，这使其成为光电子和超快半导体器件的重要材料。但是，它在环境温度下非常脆。在这里，我们通过使用微米级样品的原位压缩，展示了单晶 Ge 在很宽的温度范围内的可塑性，即使在低温下也是如此。微观机械测试在 -100°C 至 400°C 范围内进行，Ge 的同源温度范围为 0.14–0.56 T _{m 。}这个宽的温度范围包括位错介导的塑性变形的两个转变：随机到滑行（~0.31 T _m）和脆性到韧性（~0.47 T _m）过渡。Ge 中的尺寸效应对于通过部分位错的变形来说很弱，但通过完全位错更明显。本研究为从根本上理解共价半导体中温度和尺寸相关的塑性和相关缺陷行为提供了全面的知识，并为器件应用制造坚固的 Ge 基微结构提供了实用指南。