Science Daily March 18, 2022
Phase-change materials (PCMs) can switch between amorphous and crystalline states permanently yet reversibly. However, the change in their mechanical properties has largely gone unexploited. The most practical configuration using suspended thin-films suffer from filamentation and melt-quenching. An international team of researchers (UK, USA – University of Pennsylvania) used nanowires as active nanoelectromechanical systems (NEMS) to overcome these limitations. They achieved active modulation of the Young’s modulus in GeTe nanowires by exploiting a unique dislocation-based route for amorphization. The nanowire NEMS enable power-free tuning of the resonance frequency over a range of 30% and their high quality factors (Q > 104) were retained after phase transformation. To facilitate monolithic integration they utilized the intrinsic piezoresistivity with gauge factors (up to 1100). The NEMS demonstrated real-time frequency tuning in a frequency-hopping spread spectrum radio prototype. The work provides a novel framework for utilizing functional nanowires in active mechanical systems…read more. Open Access TECHNICAL ARTICLEÂ
Annotated SEM image of the phase-change NEMS device. Credit: Nature Communications volume 13, Article number: 1464 (2022)Â