Efficient Photothermal Generation by Nanoscale Light Trapping in a Forest of Silicon Nanowires

We experimentally investigate the photothermalconversion in disordered silicon nanowires (SiNWs) grown on aglass substrate by plasma-enhanced chemical vapor deposition. Thetemporal and spatial response under illumination of a 532 nm laserhas been measured by means of an infrared (IR) thermocamera.Fast heat generation and adjustable temperature increase from afew tens up to ?600 °C have been observed in a confined smallregion around the laser spot. The performing photothermalconversion is related to the efficient light trapping in SiNWs,providing enhanced absorption in the visible spectrum, andnonradiative recombination of the photogenerated carriers,typically occurring in Si. These findings combined with a lowcost,low-temperature, and large-area fabrication technology promote the disordered SiNWs as a flexible heat source well suited forapplications in multiple fields including biology, precision medicine, gas detection, and nanometallurgy.