Ultrasmooth Gold Films via Pulsed Laser Deposition

Abstract

A simple, one step technique for depositing ultrasmooth gold films using pulsed laser deposition is demonstrated by optimizing process para­meters. The smoothest film having a root‐mean‐square roughness of 0.17 nm (including the substrate roughness of 0.11 nm) for a 35 nm thick film on a silicon substrate are obtained by introducing a nitrogen flow in the chamber during deposition. We postulate that the reduction in surface roughness caused by nitrogen gas pressure in the chamber is due to the force of the gas flow acting against the flow of the plasma plume containing Au atoms. The gas acts as a filter that reduces the kinetic energy of the gold adatoms. This is the best result reported so far for a single step deposition of gold. It is a step towards low‐loss planar gold films for surface plasmon applications.

Radiofrequency Plasma‐Assisted Pulsed Laser Deposited Pt/TiOxNy Coatings on Multi‐Walled Carbon Nanotubes as Gas Diffusion Electrodes for the Oxygen Reduction Reaction

“…The ablated metal and formed NPs can be directly collected on the desired support material. [ 23–26,29 ] PLD is competitive compared with other techniques like vacuum evaporation and sputtering in terms of deposition rate, strong nanoparticle‐support interactions, chemical purity, and homogeneity of the deposited film. [ 30,31 ]…”

“…The ablated metal and formed NPs can be directly collected on the desired support material. [23][24][25][26]29] PLD is competitive compared with other techniques like vacuum evaporation and sputtering in terms of deposition rate, strong nanoparticle-support interactions, chemical purity, and homogeneity of the deposited film. [30,31] In this study, a combination of a nanosecond PLD and a lowpressure capacitively coupled radiofrequency plasma, called radiofrequency plasma-assisted pulsed laser ablation (RF-PAPLD), was used to synthesize TiN and TiO x N y coatings on multiwalled carbon nanotubes (MWCNTs) grown directly on stainless steel (SS), followed by the deposition of Pt NPs by PLD.…”

Analysis of Effects of Surface Roughness on Sensing Performance of Surface Plasmon Resonance Detection for Refractive Index Sensing Application

“…Smooth plasmonic sensors can be achieved through chemical polishing [ 25 , 26 ], using mica substrate [ 27 ], the stripping method [ 28 , 29 ], self-limiting galvanic displacement [ 30 ], chemically grown single-crystalline gold [ 31 ], laser ablation [ 32 ], helium ion beam [ 33 ], and thermal annealing [ 34 ]. Table 1 shows the remaining roughness of the plasmonic gold sensor after different surface treatments.…”

Pulse Laser Deposition Fabricating Gold Nanoclusters on a Glassy Carbon Surface for Nonenzymatic Glucose Sensing

“…13,20,27,28 In the case of Ar, the gas will confine the plasma in a smaller volume by increasing the number of collisions between the plasma and the gas molecules, which in turn reduce the velocity of the neutral gold species impinging on the substrate and hence the type of structure obtained. [29][30][31] It has been demonstrated that deposition under vacuum conditions yields dense films, whereas an inert gas environment favors the synthesis of nanoparticles with controlled size. 32 At a fixed Ar pressure, when we increased the pulse number, the amount of Au species attached to the surface of GC has also become more.…”

“…So as to improve the Ar gas pressure to 100 Pa, a very small amount of the plasma could reach the GC surface, also could not form the island structure, and thus could not supply a larger active surface area; this dropped the cathodic peak values of the GNCs/GC electrodes. 29,31,32 Figure 3B shows CV of the GNCs/GC electrodes with different pulse number; for all other experimental conditions, such as the laser energy of 200 mJ, the laser frequency of 5 Hz were kept fixed. The reduction peak currents increased with the increase of the pulse number, which reflects the increasing active sites due to the attachment of GNCs, consistent with the SEM observation stated above.…”