Raman evidence for the successful synthesis of diamane

Abstract

Diamane was prepared from the exposure of bi-layer graphene to H radicals produced by the hot-filament process. A sharp sp 3 -bonded carbon stretching mode was observed by UV Raman spectroscopy while no sp 2 -bonded carbon peak was simultaneously detected. This is the first time that Raman spectra of genuine diamane are reported, which, meanwhile, are the very first evidence for the successful synthesis of genuine diamane. First principle calculations support possible full hydrogenation and confirm the hydrogenated AB configuration to be the most stable one. We believe those results constitute a milestone in the path towards the synthesis of high-quality diamane and open the door to large-scale production. Genuine diamane consists of two crystalline sp 3 −bonded carbon layers for which half of the carbon atoms are hydrogenated while the other half bond the two layers to each other [1,2]. The material stability was first predicted by Chernozatonskii et al in 2009 [1]. The increasing interest in this new 2D wide bang-gap semiconducting material comes, in particular, from its potential use in electronics [3]. Recently, the synthesis of stable 2D nanometer-thick and crystalline sp 3 -bonded carbon, was unambiguously shown for the first time [2,4]. This breakthrough was achieved from

Fully Hydrogenated and Fluorinated Bigraphenes–Diamanes: Theoretical and Experimental Studies

“…Prof. F. Piazza's group conducted experiments on "pure" diamanes-2D diamond films completely covered by H atoms [31,37,38]. A low temperature and applied pressure lead to a transformation to ultrathin crystalline carbon films, which were successfully prepared by F. Piazza et al [37].…”

“…The T bands of the phonon dispersion corresponded to the interface between the sp 2 -C layer and hydrogenated sp 3 -C layer (Figure 11e). Reference [38] reported the first evidence for the successful synthesis of genuine diamane. Micro-Raman mapping was performed before (Figure 12a) and after (Figure 12b) exposure to the hydrogenation process promoted by hot filaments.…”

“…The typical spectrum of such a region exhibits specific features: (i) the G peak is no longer detected; (ii) the D peak that originates from defects in the graphene sheets is not observed either; (iii) a sharp peak at around 1344-1367 cm −1 occurs. Reference [38] reported the first evidence for the successful synthesis of genuine diamane. Micro-Raman mapping was performed before (Figure 12a) and after (Figure 12b) exposure to the hydrogenation process promoted by hot filaments.…”

“…The typical spectrum of such a region exhibits specific features: (i) the G peak is no longer detected; (ii) the D peak that originates from defects in the graphene sheets is not observed either; (iii) a sharp peak at around 1344-1367 cm −1 occurs. [37] and after hydrogenation (b) [38].…”

Modifying Electronic and Elastic Properties of 2-Dimensional [110] Diamond by Nitrogen Substitution

“…Several works have theoretically studied on the stability of diamane that is passivated by other atoms and molecules and also its band gap and thermal conductivity, depending on passivating molecules [15,16]. The diamane can be synthesized by exposing a bilayer graphene in order to chemically react with H or F atoms [17][18][19][20].…”