Low-temperature growth of large-scale, single-crystalline graphene on Ir(111)**Project supported by the National Key Research & Development Program of China (Grant Nos. 2016YFA0202300 and 2018YFA0305800), the National Natural Science Foundation of China (Grant Nos. 61888102 and 51872284), the Chinese Academy of Sciences (CAS) Pioneer Hundred Talents Program, the Strategic Priority Research Program of Chinese Academy of Sciences (Grant Nos. XDB30000000 and

Abstract

Iridium is a promising substrate for self-limiting growth of graphene. However, single-crystalline graphene can only be fabricated over 1120 K. The weak interaction between graphene and Ir makes it challenging to grow graphene with a single orientation at a relatively low temperature. Here, we report the growth of large-scale, single-crystalline graphene on Ir(111) substrate at a temperature as low as 800 K using an oxygen-etching assisted epitaxial growth method. We firstly grow polycrystalline graphene on Ir. The subsequent exposure of oxygen leads to etching of the misaligned domains. Additional growth cycle, in which the leftover aligned domain serves as a nucleation center, results in a large-scale and single-crystalline graphene layer on Ir(111). Low-energy electron diffraction, scanning tunneling microscopy, and Raman spectroscopy experiments confirm the successful growth of large-scale and single-crystalline graphene. In addition, the fabricated single-crystalline graphene is transferred onto a SiO2/Si substrate. Transport measurements on the transferred graphene show a carrier mobility of about . This work provides a way for the synthesis of large-scale, high-quality graphene on weak-coupled metal substrates.