Image of the week: graphene islands

By Jennifer Sanders on October 19, 2015

Graphene is one of the most studied materials, possessing extraordinary properties including great tensile strength — on the order of GPa (gigapascals) — and is popular in the fields of electronics, semiconductors and photovoltaics. One method of producing good quality graphene films involves chemical vapour deposition (CVD) on a copper surface, which is relatively inexpensive and allows large scale production.

In a recently published JPhysD paper, researchers from Russia have studied the CVD process for graphene film production, specifically probing the ideal temperature range, typically 1000-1080 °C to achieve good quality films whilst taking into account the melting point of copper at 1083 °C. Melting of the copper, and subsequent forming of a liquid layer during the synthesis process, may affect the resultant graphene film. A A Pakhnevich et al have shown that the copper does in fact melt at growth temperatures of 1000 and 1050 °C; markedly below copper’s bulk melting temperature. The liquid layer was found to be capable of wetting the graphene film and its flow characteristics affected the orientation and waviness of graphene islands formed during the synthesis process. The copper’s surface flow creates alignment of the islands along ‘guide curves’ (dashed lines) which can be seen in the SEM image below.