Wafer-scale transfer-free process of multi-layered graphene grown by chemical vapor deposition

Abstract

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 (SLG-MLG) has recently garnered much more interest. Here we report an original method to obtain a 4-inch wafer fully covered by 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, used as a catalyst for the MLG growth via CVD. X-ray photoelectron spectroscopy proves that the layer of Mo is etched away and no residues of Mo are trapped beneath 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 Mo layer etch. These results mark a significant step forward for numerous applications of SLG-MLG on wafer scale, ranging from micro/nano-fabrication to solar cells technology.

Low-Humidity Sensing Properties of Multi-Layered Graphene Grown by Chemical Vapor Deposition

“…Of note, in other works [27,49], as well as through the Raman analysis, we have proved that the grown material consists of MLG rather than thin graphite [50]. Figure 2a shows jagged surface of MLG with a roughness of ~3 nm [49]. The jagged surface is further attested by the SEM image (Figure 2b).…”

Overview of Engineering Carbon Nanomaterials Such As Carbon Nanotubes (CNTs), Carbon Nanofibers (CNFs), Graphene and Nanodiamonds and Other Carbon Allotropes inside Porous Anodic Alumina (PAA) Templates

“…For instance, Figure 21 a illustrates the procedure to obtain a positive pattern with a transfer-free approach. First, the graphene is grown by a CVD process, subsequently, the graphene is released from the catalyst [ 205 ], then, aluminium can be sputtered or evaporated on the graphene and afterwards the anodization process can be performed until the graphene is reached, followed by wet etching to open the pores. At this stage, the PAA act as a mask similarly as in Zeng et al [ 201 ], therefore, an O 2 plasma can be used to etch the exposed graphene and finally, remove the PAA via wet chemical etching.…”