Toward clean suspended CVD graphene

Abstract

The application of suspended graphene as electron transparent supporting media in electron microscopy, vacuum electronics, and micromechanical devices requires the least destructive and maximally clean transfer from their original growth substrate to the target of interest. Here, we use thermally evaporated anthracene films as the sacrificial layer for graphene transfer onto an arbitrary substrate. We show that clean suspended graphene can be achieved via desorbing the anthracene layer at temperatures in the 100 °C to 150 °C range, followed by two sequential annealing steps for the final cleaning, using Pt catalyst and activated carbon. The cleanliness of the suspended graphene membranes was analyzed employing the high surface sensitivity of low energy scanning electron microscopy and x-ray photoelectron spectroscopy. A quantitative comparison with two other commonly used transfer methods revealed the superiority of the anthracene approach to obtain larger area of clean, suspended CVD graphene. Our graphene transfer method based on anthracene paves the way for integrating cleaner graphene in various types of complex devices, including the ones that are heat and humidity sensitive.

Anthracene modified graphene for C60/C70 fullerenes capture and construction of energy storage materials

“…Raise of the higher binding energy peaks intensity is caused by increased amount of carbon atoms with sp 3 hybridization and was expected after successful addition of anthracene malonate to double bonds of graphene surface. The second biggest peak with 22% abundance is centered at 285.4 eV and is attributed to C-C carbon atoms (Yulaev et al 2016). The other two peaks are observed due to presence of C-O ester (3%at) and C=O carbonyl (5%at) carbon atoms and where observed at 286.3 and 288.0 eV, respectively (Zuo et al 2013).…”

Cleaning graphene: Comparing heat treatments in air and in vacuum

“…In addition, hydrocarbon impurities are directly absorbed from the atmosphere onto the surface. Their chemical nature is still not precisely known, but most studies point to (‐CH 2 ‐) and (‐CH 3 ‐) groups ; carboxyl, methoxy, and sp 3 ‐hybridized carbon ; and (CO) functional groups . Finally, mobile contamination may be pinned into place by the electron beam .…”

Deterministic transfer of optical-quality carbon nanotubes for atomically defined technology

“…To pick up long CNTs and release them on arbitrary substrates with minimum contamination, we use thin and large-area organic crystals that do not require wet processes or high-temperature treatments. Anthracene, which consists of three benzene rings, meets such requirements 22 , 23 . We expect the similarity of molecular structure between anthracene and CNTs to lead to strong π – π interactions 24 , possibly improving the efficiency of picking up CNTs from the growth substrates.…”