TY - JOUR
T1 - Localized Physical Vapor Deposition via Focused Laser Spike Dewetting of Gold Thin Films for Nanoscale Patterning
AU - Ma, Tianxing
AU - Nitzsche, Michael P.
AU - Gamboa, Arielle R.
AU - Saro-Cortes, Valeria
AU - Singer, Jonathan P.
N1 - Publisher Copyright: © 2018 American Chemical Society.
PY - 2019/1/25
Y1 - 2019/1/25
N2 - Focused laser spike (FLaSk) excitation has been demonstrated as a reliable technique for the patterning of micro-to-nanoscale features locally by thermocapillary shear of thin films. Recent work on polymer thin films has revealed that overlapping laser scans can leverage coupled thermal and fluid effects to create subwavelength patterns. Compared to polymeric films, metallic thin films possess both a lower melt viscosity and higher surface tension. Here, we investigate overlapping effects in the dewetting of ∼15 nm gold thin films on borosilicate and quartz glass substrates with a 532 nm continuous wave laser. During this process, FLaSk initiates capillary and thermocapillary dewetting simultaneously. Further, the low oxidation potential and high vapor pressure of gold lead to nonequilibrium vaporization during heating. Since the parameters of overlapping scans control the amount of material that is heated and to what temperature it is heated, selection of laser power, scanning distance, writing speed, and numerical aperture results in particles with different sizes and spacing deposited on the writing substrates or a positioned superstrate through a laser-induced localized physical vapor deposition (LILPVD) process. If the laser parameters are selected within a specific working range, uniform or periodic particle distributions can be repeatably deposited in this fashion, which can then be used as seeds for nanomaterial growth. In addition, if the substrate melts during FLaSk, the viscous force of the liquid-on-liquid dewetting broadens the range of patterning conditions by resisting the motion of the gold leading to more uniform particles over a large range of parameters.
AB - Focused laser spike (FLaSk) excitation has been demonstrated as a reliable technique for the patterning of micro-to-nanoscale features locally by thermocapillary shear of thin films. Recent work on polymer thin films has revealed that overlapping laser scans can leverage coupled thermal and fluid effects to create subwavelength patterns. Compared to polymeric films, metallic thin films possess both a lower melt viscosity and higher surface tension. Here, we investigate overlapping effects in the dewetting of ∼15 nm gold thin films on borosilicate and quartz glass substrates with a 532 nm continuous wave laser. During this process, FLaSk initiates capillary and thermocapillary dewetting simultaneously. Further, the low oxidation potential and high vapor pressure of gold lead to nonequilibrium vaporization during heating. Since the parameters of overlapping scans control the amount of material that is heated and to what temperature it is heated, selection of laser power, scanning distance, writing speed, and numerical aperture results in particles with different sizes and spacing deposited on the writing substrates or a positioned superstrate through a laser-induced localized physical vapor deposition (LILPVD) process. If the laser parameters are selected within a specific working range, uniform or periodic particle distributions can be repeatably deposited in this fashion, which can then be used as seeds for nanomaterial growth. In addition, if the substrate melts during FLaSk, the viscous force of the liquid-on-liquid dewetting broadens the range of patterning conditions by resisting the motion of the gold leading to more uniform particles over a large range of parameters.
KW - dewetting
KW - focused laser
KW - gold
KW - nanoparticles
KW - physical vapor deposition
KW - thin film
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U2 - 10.1021/acsanm.8b02178
DO - 10.1021/acsanm.8b02178
M3 - Article
SN - 2574-0970
VL - 2
SP - 586
EP - 597
JO - ACS Applied Nano Materials
JF - ACS Applied Nano Materials
IS - 1
ER -