Gold surface with gold nitride–a surface enhanced Raman scattering active substrate

Abstract

The nitration of gold surfaces is a nonpolluting method, which can lead to large scale production of substrates with remarkable properties and applications. We present a topographical study of the nanoscale structure of the gold nitride surfaces produced by radio frequency ͑rf͒ nitrogen plasma etching of thin gold films. Atomic force microscopy images taken after rf etching reveal the striking appearance of the cluster assembly with large clusters surrounded by small clusters ͑7.9Ϯ 1.4 and 2.3Ϯ 0.9 nm, respectively͒ appearing to exhibit an attractive interaction. We discuss the possible mechanism for this attraction based on a colloid model by Messina et al. ͓Phys. Rev. Lett. 85, 872 ͑2000͔͒. This surface exhibits a notable surface enhanced Raman scattering effect demonstrated with L-alanine and rhodamine-6G. The significance of this work is that we found that this SERS active gold nitride surface can be prepared in just one step: by nitrogen plasma etching a thin gold film. Until now most SERS active gold cluster covered surfaces have been prepared in several steps very often requiring complex lithography.

Gold Nitride: Preparation and Properties

“…Atomic force microscopy (AFM) investigations of the nanoscale topography of gold nitride surfaces produced by plasma etching thin gold films [12][13][14] revealed an island or cluster morphology with large clusters of gold nitride surrounded by small clusters of the same material (cluster diameters were found to be 7.9 ± 1.4 and 2.3 ± 0.9 nm, respectively). This surface exhibits a notable Surface Enhanced Raman Scattering (SERS) effect, demonstrated with L-Alanine (5 9 10 -4 mol/L in aqueous solution) and rhodamine-6G as an analyte in ethanol solution at a concentration of 10 -6 mol/L [13,14].…”

“…Our group has since reported the large scale production of gold nitride using RIS and plasma etching without the need for UHV [6,[10][11][12][13][14], reducing the time and cost associated with nitridation. In Fig.…”

“…There are a number of different techniques by which gold nitride films can be produced such as ion implantation [8,9], reactive ion sputtering (RIS) [6,10,11], plasma etching [6,[12][13][14], reactive pulsed laser deposition [7] and plasma assisted physical vapor deposition (PAPVD) using pulsed arc discharge [15,16]. Moreover, gold nitride species have been found to exist in the gas phase: Drenck et al [17] observed the formation of nitrogen-gold AuN n -anions and dianions.…”

Fabrication of porous microrings via laser printing and ion-beam post-etching

“…The white circles show the actual dimensions of the microrings. The scale bar is 500 nm everywhere accelerated nitrogen ions 42,43 . Also, Au x N films were fabricated, using ablative pulsed laser deposition in a N 2 containing atmosphere 44 .…”

Investigation of boron and nitrogen ion beam implantation in gold thin films for ohmic MEMS switch contact improvement

“…This type of small "clusters" is exclusively present on N10%. Coupling AFM, GI-XRD and results from [22], it is assumed that small "clusters" are nitride precipitates. Using the previous results, the following scenario of hardening mechanism is proposed.…”