Low-temperature fabrication of nanographene on a copper substrate using pentacene

Highlights: • Nanographenes are synthesized on a copper substrate at 250 °C. • Precursors are generated from pentacene and H₂ gas by a heated tungsten mesh. • A clean copper surface is achieved by atomic hydrogen before nanographene synthesis. • The obtained Raman spectrum had a shape similar to graphene nanoribbons. -- Abstract: We developed a low-temperature fabrication method for nanographene on a copper (Cu) substrate. This process is called hot-mesh deposition (HMD) and uses pentacene, H₂, and a tungsten (W) mesh. In HMD, pentacene and H₂ molecules decompose on a heated W mesh placed between a pentacene source in a molybdenum boat and a Cu substrate. A clean surface was obtained using atomic hydrogen treatment prior to nanocarbon film formation. The nanocarbon films consisted of nanographenes, which formed on the cleaned Cu substrate. The peaks due to the D and D' bands of nanographene were observed in the Raman spectrum. It was found that nanographene could be produced by HMD even at temperatures as low as 250 °C. It is considered that the key factors for the low-temperature formation of nanographene are a clean Cu surface, and the reaction of pentacene with the 6,13-dihydropentacene generated on the heated W mesh.