Fabrication of controllably variable sub-100  nm gaps in silver nanowires by photothermal-induced stress

Abstract

A technique to fabricate nanogaps with controllably variable gap width in silver (Ag) nanowires (NWs) by photothermal-induced stress utilizing a focused continuous-wave laser (532 nm) is presented. For the case of an Ag NW on gold thin film, a gap width starting from ∼20 nm is achieved with a critical minimum power (CMP) of about 160 mW, whereas in the case of an Ag NW placed on top of a zinc oxide NW, the attained gap width is as small as a few nm (<10 nm) with a CMP of only ∼100 mW. In both cases, the CMP is much lower as compared to the required CMP (∼280 mW) for an Ag NW placed on a bare silica substrate. The photothermal-induced stress combined with Rayleigh instability, melting, and sublimation of Ag aids in breaking the Ag NW. In particular, the former one plays a key role in attaining an extremely narrow gap. This technique to fabricate sub-100 nm nanogaps in metal NWs can be extensively implemented in fabrication and maintenance of nanomechanical, nanoplasmonic, and nanoelectronic devices.

Nanojoining and tailoring of current–voltage characteristics of metal-P type semiconductor nanowire heterojunction by femtosecond laser irradiation

“…2(c). Additional irradiation causes the Ag nanowire to melt into a series of small nanospheres due to the Raleigh instability from localized heating, 25,26 eventually breaking the Ag-CuO nanowire heterojunction [Fig. 2(d)].…”

Photothermal Imaging of Individual Nano-Objects with Large Scattering Cross Sections

“…Compared with metallic nanoparticles supporting the localized surface plasmon resonances, metallic NWs with the extremely large aspect ratio and surface to volume ratio enable both the electromagnetic field confinement in the subwavelength scale and the propagation of surface plasmons. − The large electromagnetic field enhancement around the NWs has been employed in the field such as surface-enhanced Raman spectroscopy, , photocatalysis, and solar cells. − The subwavelength light-guiding effect is of enormous interest because of its potential applications in building nanophotonic circuits. − The field confinement and propagation of surface plasmons also make metallic NWs attractive for investigating the strong light-matter interactions. − Also, the metallic NWs yield singular thermal properties − and provide the potential applications in the field such as transparent conductive film, , transparent heater, , nanowelding, , and so on.…”

“…26−29 The field confinement and propagation of surface plasmons also make metallic NWs attractive for investigating the strong light-matter interactions. 30−32 Also, the metallic NWs yield singular thermal properties 33−35 and provide the potential applications in the field such as transparent conductive film, 36,37 transparent heater, 38,39 nanowelding, 39,40 and so on.…”

Flash Ablation of Tunable and Deep-Subwavelength Nanogap by Using a Spatially Modulated Femtosecond Laser Pulse for Plasmonic Application

“…5,6 There exist many traditional methods of nanogap fabrication. 7,8 The first category is named subtractive technique represented by electron beam lithography (EBL) and etching, 9,10 focused ion beam (FIB) 11 direct etching, and electromigration. 12 The lithography and etching method is the most widespread nanogap fabrication method, achieving a high resolution of sub-100 nm.…”