Driving with temperature the synthesis of graphene films on Ge(110)

TL;DR

This study explores how the temperature during chemical vapor deposition affects the quality of graphene films on Ge(110), revealing that higher temperatures near the melting point improve film quality due to surface changes.

Contribution

It demonstrates the critical role of growth temperature and surface state in optimizing graphene synthesis on germanium, with implications for general Ge orientations.

Findings

Graphene quality improves significantly at 910-930°C.

Formation of quasi-liquid Ge surface enhances atom diffusivity.

Process is applicable to various Ge orientations.

Abstract

We systematically investigate the chemical vapor deposition growth of graphene on Ge(110) as a function of the deposition temperature close to the Ge melting point. By merging spectroscopic and morphological information, we find that the quality of graphene films depends critically on the growth temperature improving significantly by increasing this temperature in the 910-930 {\deg}C range. We correlate the abrupt improvement of the graphene quality to the formation of a quasi-liquid Ge surface occurring in the same temperature range, which determines increased atom diffusivity and sublimation rate. Being observed for diverse Ge orientations, this process is of general relevance for graphene synthesis on Ge.