Clarifying Contribution of SERS Mechanism Based on Semiconductor Material - ZnO Microtube in Probing Methylene Blue

Surface-enhanced Raman spectroscopy (SERS) is a powerful technique for identifying molecular species, but it has been primarily limited to noble metal supports. The use of semiconductor materials as SERS surfaces has been attempted and has generally proven less effective than metal materials. It is known due to semiconductor materials' less efficient surface plasmon resonance (SPR) effect mechanism. This study clarified the SERS mechanism based on semiconductor material - ZnO microtube in probing methylene blue (MB) as an equal contribution of charge transfer and SPR mechanisms. Using Herzberg-Teller-surface selection rules, the charge transfer contribution in the SERS mechanism was estimated at approximately 50%. The limit of detection of ZnO microtube was achieved at 10-7 M, and the best enhancement factor was of 6.1×105.