Laser micro annealing conditioning for the suppression of statistical scatter in freestanding Sb2Te3 nanowire resistance

Abstract The effect of long-term laser micro annealing (LMA) on the statistical resistance scatter in freestanding Sb2Te3 layered nanowires (NWs) was studied during the formation of ohmic contacts. The process was developed and optimized by monitoring the evolution of the NW resistance and the DC photo-responsivity and correlating the characteristics to the structural degradation observed using micro Raman spectroscopy. The NWs were transferred to and integrated into Ti/Au coplanar strip lines on flexible polyethylene terephthalate (PET) substrates designed for optoelectronic applications. Four different stages in the NWś resistance were revealed. The optimal “time-annealing” interval was identified, in which the lowest NW resistance was determined and in which no evidence for structural degradation processes in the active central NWś region was found. Low dark currents below 10-5A at 100 mV bias as well as high DC photo-responsivity ∼ 0.6 A/W were achieved rendering the nanowire devices as very promising candidates for highly sensitive infrared optoelectronics. The statistical scatter in the NWś resistance was minimized to a range of ±10% of the total value by conditioning the contact/annealed regions of the NWs individually and tuning the resistance of these regions as a function of the total laser annealing time.