A silicon membrane-silver nanoparticles SERS chip for trace molecules detection

Abstract

Detecting the traces of molecules in the surrounding environment are the technical challenges associated with contaminant control during space apparatus assembly stages, space research, food production, medicine, environmental control, military, etc. However, the detection of the traces of the molecules of contaminants in the environment is a challenge because the number of target molecules can be as low as part-per-billion (ppb) in the air. Moreover, the Organic Volatile Compounds in the air may have very low adsorption to the sensing element. This work presents a novel Surface Enhanced Raman spectroscopy (SERS) platform for molecular sensors based on the hybrid nanoplasmonic silicon membrane integrated with gas micropump. The proposed solution of the problem is to increase the probability of interaction of analytes with SERS substrate plasmonic structures by the pumping gas or liquid with contaminants through the silicon membrane decorated with silicon flower like nano-structures (“hot spots“). The main objective of theoretical computational design of the sensor is to determine the optimal conditions for trace molecules flow through and interaction with SERS substrate (“hot spots“) to increase the Raman scattering. The computer simulation of gas flow with the purpose to optimize the sensor chip structure was made using SolidWorks software. The sensor chip structure was designed, simulated and manufactured using 3D printing. The measured results show that the proposed sensing platform is of high sensitivity. The SERS spectra of the anizole vapors (4,6 × 10−9 M) and crystal violet solution (10 × 10−9 M) were recorded using Raman spectrometer (NTEGRA Spectra, NT-MDT Inc.) equipped with 532 nm laser. It was found that the developed SERS platform allows to achieve the nanomolar sensitivity in gas detection and reliably identify the type of analyte based on SERS spectral fingerprint.