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

• Published in: FlatChem 2020-05, Vol.21, p.100164, Article 100164
• Main Authors: Mikulics, M., Lu, J.G., Huang, L., Tse, P.L., Zhang, J.Z., Mayer, J., Hardtdegen, H.
• Format: Article
• Language: English
• Subjects: Correlative studies; Hybrid nanodevice; Laser annealing; Local contact formation; Nanowire photodetector
• ISSN: 2452-2627; 2452-2627
• DOI: 10.1016/j.flatc.2020.100164

[Display omitted] •Systematic influence of laser micro annealing time on nanowire properties studied.•Four different conditioning regions identified.•Correlation between structural and electrical properties found.•Statistical resistance scatter in nanowires suppressed.•Layered Sb2Te3 NWs for highly sensitive infrared photodetectors demonstrated. 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 NW 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 NWs’ region was found. Low dark currents below 10−5 A 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 NW 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.