Electrons and other charge carriers have been demonstrated to move faster in germanium tin (GeSn) than in silicon (Si) or germanium, enabling lower operation voltages and smaller footprints in vertical than in planar devices. This finding by an international group of researchers points to the promise of vertical transistors made of germanium as candidates for future low-power, high-performance chips and possibly quantum computers. 
Schematic of a vertical p-field effect transistor with GeSn source and source and Ge channel. Source: Nat. Commun. Eng 2, 7 (2023)
These transistors exhibit an electron mobility that is 2.5 times higher than a comparable device composed of pure Ge. GeSn is also compatible with the conventional complementary metal oxide semiconductor (CMOS) process for chip fabrication and could be integrated directly into conventional silicon chips with existing production lines.
The GeSn alloys offer a tunable energy bandgap and their use on top of Ge nanowires has been shown to enhance metal oxide semiconductor field effect transistor performance. An additional benefit is that the materials can be grown in the same epitaxy reactors as Si and SiGe alloys, enabling an all-group IV optoelectronic semiconductor platform that can be monolithically integrated on Si.
The research conducted by scientists from Forschungszentrum Jülich (Germany), CEA-Leti (France), University of Leeds (U.K.), IHP- Innovations for High Performance Microelectronics (Germany), Peter Grünberg Institute 9 (Germany) and RWTH Aachen University (Germany) is published in Nature Communications Engineering.
