Wafer scale transfer free process of mul

Chemical vapour deposition (CVD) has emerged as the dominant technique to combine high quality with large scale production of graphene. The key challenge for CVD graphene remains the transfer of the film from the growth substrate to the target substrate while preserving the quality of the material. Avoiding the transfer process of single or multi-layered graphene has recently garnered much more interest. Here we report an original method to obtain a 4-inch wafer fully covered by multi-layered graphene (MLG) without any transfer step from the growth substrate. We prove that the MLG is completely released on the oxidized silicon wafer. A hydrogen peroxide solution is used to etch the molybdenum layer, utilized as a catalyst for the MLG growth via CVD. X-ray photoelectron spectroscopy confirms that the layer of molybdenum is etched away and no residues of molybdenum are trapped beneath the MLG. Terahertz transmission near-field imaging, as well as Raman spectroscopy and atomic force microscopy, show the homogeneity of the MLG film on the entire wafer after the molybdenum layer etch. These results mark a significant step forward for numerous applications of SLG-MLG on wafer scale, ranging from micro/nano-fabrication.