研究目的
The design of efficient substrates for surface-enhanced Raman spectroscopy (SERS) for large-scale fabrication at low cost is an important issue in further enhancing the use of SERS for routine chemical analysis.
研究成果
This systematic study proves the possibility of increasing the surface roughness of sputtered silver films through application of different rf plasma treatments as an alternative to the widely employed method of electrochemical surface roughening of silver films. Different reactive plasma gas compositions as well as different plasma parameters used in the particular plasma treatments result in a variety of different SERS silver substrates with tunable morphology and attractive enhancement factors. A combination of an oxidizing plasma together with a reducing plasma results in the formation of complex three-dimensional silver morphologies showing a huge enhancement factor due to the formation of SERS hot spots. The SERS enhancement of the as-sputtered 200 nm silver film is greatly enhanced by an appropriate plasma treatment reaching about 30-fold enhancement compared to a commercial SERS substrate and about 1200-fold compared to the untreated silver film. At the same time it was also found that ultrathin transparent silver films can be used as efficient SERS substrates. Heating of the silver film under a subsequent oxidative/reductive rf plasma treatment enables the formation of a silver-nanosponge morphology directly on the glass substrate. The morphologies fabricated by various plasma treatment processes are stable over the course of several weeks and can even be recovered and re-used after initial analytical use through employing a mild argon plasma treatment.
研究不足
The study does not mention any specific limitations.