Harish Chevva – Seminar/PhD Preliminary Defense – Monday, December 4, 2017 at 10:00 A.M.

JSNN – Harish Chevva – Ph.D. Preliminary Defense/Monday Seminar

Candidate: Harish Chevva

Advisor and Committee Chair: Jianjun Wei, Ph.D.

Department: Nanoscience

Time: 10:00 A.M. – 12:00 P.M.

Location: JSNN 209 Open Room

2907 E. Gate City Blvd., Greensboro, NC 27401

Title: “Integrated Silver Nanoparticles(NPs)/Nanowires(NWs) & 2D Material MoS2 Platform for Surface Enhanced Raman Spectroscopy(SERS) Applications.”


Single molecule spectroscopy paves a way to analyze single molecule characteristics which are more meaningful and helps in the deep understanding of molecule behavior in the specific environment than the characteristics obtained by analyzing an ensemble of molecules in similar biological systems. Surface Enhanced Raman Spectroscopy(SERS) is a recent most reliable technique employing for obtaining single molecule spectroscopy. Metal nanostructures and 2D materials have been studied in various forms and combinations for last decade to obtain high Raman signal enhancement in the presence of the same due to SERS. This attributes the researchers to move in the way to obtain Raman signal enhancement to the level of 1012 counts, such that single molecule spectroscopy is possible. In this research, new and unique self-grown silver(Ag) nanowires(NWs) on Chitosan polymer substrate is used as SERS platform for single molecule spectroscopy and further proposed a way for integrating synthesized Ag NWs with few to monolayer 2D material MoS2 and the combination with Gold (Au) thin film for the highest possible, controlled and repeatable SERS enhancement for single-molecule spectroscopy. Initial experiments for spectrum enhancement analysis and detection is performed on Raman active molecule Rhodamine 6 G (R6G) at various molar concentrations, from 10-3 M to as low as 10-12 M concentration on alone Ag NWs platform. Finite Difference Time Domain(FDTD) analysis is employed to understand the underlying science behind the increase in enhancement when the hybrid platform of Ag NWs, 2D material MoS2 platform, and Au thin film is subjected for detection measurements in comparison with individual platforms.