Growth of large aspect ratio AuAg bimetallic nanowires on Si(110) substrate

Anjan Bhukta, Puspendu Guha, Biswarup Satpati, Paramita Maiti, Parlapalli V. Satyam*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Large aspect ratio bimetallic nanowire structures comprise potential applications in areas such as higher catalytic activity and surface Raman enhancement spectroscopy (SERS) substrates. By using the highly anisotropic ultra-clean Si(110) surface and with initial growth of sub monolayer (ML) Ag on such surface, a high aspect ratio AuAg bimetallic nanostructures can be formed. We report on the formation of large aspect ratio (>7.2 ± 0.8) AuAg nanowires on ultra-clean Si(110) surfaces using 0.5 ML Ag followed by 3.0 ML Au using molecular beam epitaxy (MBE) at a growth temperature of 300 °C. Under similar growth conditions without pre-deposition of Ag and only with deposition of 3.0 ML of Au consequences smaller aspect ratio (2.1 ± 0.1) monometallic Au nanostructures. The enhancement in aspect ratio of the nanostructures is attributed to the formation of one dimensional Ag layer (prior to Au growth) and Au-Ag bimetallic intermixing at elevated temperature. Considering deposition of 3.0 ML Au, a regime of substrate temperature ≈ 270–330 °C is found to be optimum to growth some of high aspect ratio (>25.0) AuAg nanowires as well. Exterior of this regime, at lower temperature due to low mobility of the ad-atoms and at higher temperature due to probable inter-diffusion of Ag, such extremely high aspect ratio AuAg nanowires found to be infrequent to grow. For growth at substrate temperature 300 °C, mean aspect ratio of the AuAg nanostructures is gradually increased in accordance with Au thickness up to 3.0 ML due to preferential accumulation of ad-atoms (Au, Ag) along Si〈11¯0〉 and thereafter reduces for adequate accumulation along Si〈001〉.

Original languageEnglish
Pages (from-to)337-344
Number of pages8
JournalApplied Surface Science
StatePublished - 15 Jun 2017
Externally publishedYes


  • AuAg bimetallic nanostructures
  • Molecular beam epitaxy (MBE)
  • Scanning electron microscopy (SEM)
  • Scanning transmission electron microscopy
  • Si(110)


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