Facile Fabrication of Spherical Nanoparticle‐Tipped AFM Probes for Plasmonic Applications

Understanding the plasmonics of nanostructured atomic force microscopy tips

“…In recent years controlled nanostructuring of the tip apex with a distinct subwavelength-size metallic feature has been explored in order to engineer and tune a plasmonic optical antenna * Email: jjb12@cam.ac.uk; Site: www.np.phy.cam.ac.uk precisely at the apex and better incorporate more localised multipolar plasmons [16][17][18][19][20][21] Scattering resonances in the visible-NIR spectrum have been directly measured on a subset of these [25,26,29] while other reports use improvements in the field enhancement as a measurement of antenna quality [20,21,28]. In such cases the field enhancement has been attributed to give improvements by an order of magnitude through plasmon excitation [20,23,24,29].The simplest geometry for a tip apex is a spherical nanoparticle (NP), giving LSPs similar to those in an arXiv:1607.06591v1 [physics.optics] …”

“…In recent years controlled nanostructuring of the tip apex with a distinct subwavelength-size metallic feature has been explored in order to engineer and tune a plasmonic optical antenna * Email: jjb12@cam.ac.uk; Site: www.np.phy.cam.ac.uk precisely at the apex and better incorporate more localised multipolar plasmons [16][17][18][19][20][21]. Etching [21,22], focussed-ion-beam machining [23][24][25], selective deposition [26], nanoparticle pickup [27], nanostructure grafting [28] and electrochemical deposition [29] have all been successfully used to nanostructure optical antenna tips. Scattering resonances in the visible-NIR spectrum have been directly measured on a subset of these [25,26,29] while other reports use improvements in the field enhancement as a measurement of antenna quality [20,21,28].…”

“…Etching [21,22], focussed-ion-beam machining [23][24][25], selective deposition [26], nanoparticle pickup [27], nanostructure grafting [28] and electrochemical deposition [29] have all been successfully used to nanostructure optical antenna tips. Scattering resonances in the visible-NIR spectrum have been directly measured on a subset of these [25,26,29] while other reports use improvements in the field enhancement as a measurement of antenna quality [20,21,28]. In such cases the field enhancement has been attributed to give improvements by an order of magnitude through plasmon excitation [20,23,24,29].…”

“…Scattering resonances in the visible-NIR spectrum have been directly measured on a subset of these [25,26,29] while other reports use improvements in the field enhancement as a measurement of antenna quality [20,21,28]. In such cases the field enhancement has been attributed to give improvements by an order of magnitude through plasmon excitation [20,23,24,29].…”

“…Spherical tips are either 300 nm diameter, 50 nm Au-coated NanoTools B150 AFM probes or electrochemically-deposited AuNP-on-Pt AFM probes, fabricated in-house [29] (shown in Fig. 2).…”