Ultrafast investigation of thermomechanical energy transfer in InAs nanowires

Building on our recent studies on InAs nanowire forest [1] as well as nanoparticles [2], here we investigate the thermomechanical energy transfer mechanisms occurring in individual InAs nanowires exploiting ultrafast time-resolved spectroscopy [3], [4]. Aiming to access the main parameters governing the energy transport, this contactless technique is used to probe heat transfer dynamics and vibrational modes propagation optically triggered inside the nanostructure by a femtosecond laser pulse. The influence of substrate on the thermal diffusion is addressed and the thermal conductance at the interface with the polymethyl methacrylate (PMMA) supporting layer is quantified. First and second harmonic of the nanowire breathing mode are observed.