SIMULATION, FABRICATION AND CHARACTERIZATION OF GRATING AS SERS SUBSTRATES TO DETECT EXPLOSIVE MATERIAL

• Main Author: Destarina, Lisa
• Format: Theses
• Language: Indonesia
• Subjects: Fisika
• Online Access: https://digilib.itb.ac.id/gdl/view/41304
• Institution: Institut Teknologi Bandung

Detection of TNT is important for forensic purpose in order to prevent terrorism acts. Raman spectroscopy is versatile method that can be used to detect TNT due to the ability to detect material into molecular level with simple preparation of sample, fast results, little amount of sample and non-destructive. Otherwise, the spectrum intensity is weak and be swamped by other background emission so that it decreases the sensitivity. In this research was done Raman signal enhancement using plasmonic grating as SERS substrates for laser 785 nm and incidence angle parallel with normal incidence. Grating was chosen because it can be controlled technologically and simple for application if it is compared with prism coupling. Stage to create SERS substrates are simulation using RCWA method to decide SPR wavelength due to when SPR occurs, there will be local enhancement that only achieve with certain geometry structure. Then fabcrication process was done using nanoimprint lithography method. After finishing fabrication process, SERS substrates were characterized to look the SPR characterization, Raman signal and topology of structure. The biggest enhancement structure then used to detect TNT. Optimization SERS-substrates achieved structure with period 720 nm, grating depth 400 nm and gold thickness 60 nm. But, due to technically limitation, the period that can be produced is 850 nm with grating depth 210 nm and 310 nm. Nevertheless, substrates can show Raman signal enhancement. The biggest enhancement showed by substrates with period 850 nm, grating depth 310 nm, gold thickness 80 nm and filling factor 0.5. SERS substrates can detect methylene blue up to 1x10-4 M and TNT up to 1x10-1 M