Crystalline phase induced Raman enhancement on molybdenum carbides

Abstract

Here we demonstrate crystalline phase induced Raman enhancement on molybdenum carbide materials (β-Mo₂C and α-MoC). From all the studied target molecules (rhodamine 6G, crystal violet and methylene blue), the Raman enhancement on β-Mo₂C is 2–4 times higher than that on α-MoC. Spectroscopic and theoretical calculations reveal that β-Mo₂C has a lower electron work function and a higher density of states near the Fermi level than α-MoC, which promotes the charge transfer and photo induced charge transfer processes from probe molecules to the substrate.