Operando strain mapping in mid-infrared GeSn nanowire photo-transistors

We propose to employ Scanning X-ray Diffraction Microscopy (SXDM) to investigate the spatial distribution of strain and heat in functional transistors based on alloyed Ge1-xSnx core-shell nanowires. Spatial mapping of three asymmetric Bragg reflections will reveal the following features in the wires: a) all components of the lattice strain tensor εij and rotation tensor wij, b) localized fluctuations of stoichiometry, c) mechanical deformations induced by the geometry and fabrication. Moreover, we will investigate the same devices under different applied voltages to observe thermomechanical strain, caused by resistive heating, and correlate the mechanical deformation to the X-ray Beam Induced Current (XBIC) signal.