Raman spectroscopy investigation of the H content of heated hard amorphous carbon layers

Cedric Pardanaud (1) , C. Martin (1) , P. Roubin (1) , G. Giacometti (1) , C. Hopf (2) , T. Schwarz-Selinger (2) , W. Jacob (2)

1 PIIM - Physique des interactions ioniques et moléculaires
2 IPP - Max-Planck-Institut für Plasmaphysik [Garching]

We revisit here how Raman spectroscopy can be used to estimate the H content in hard hydrogenated amorphous carbon layers. The H content was varied from 2 at.% to 30 at.%, using heat treatments of a a-C:H, from room temperature to 1300 K and was determined independently using ion beam analysis. We examine the correlation of various Raman parameters and the consistency of their thermal evolution with thermo-desorption results. We identify a weak band at 860 cm-1 attributed to H bonded to C(sp2). We show that the HD/HG parameter (Height ratio between the D and G bands) is quasi-linear in the full range of H content and can thus be used to estimate the H content. Conversely, we show that the m/HG parameter (ratio between the photoluminescence background, m, and the height of the G band), often used to estimate the H content, should be used with care, first because it is sensitive to various photoluminescence quenching processes and second because it is not sensitive to H bonded to C(sp2).

Mots clés: Amorphous hydrogenated carbon; Raman spectroscopy; Hydrogen retention

Domaines: Chimie-Physique [physics.chem-ph]

Cedric Pardanaud, C. Martin, P. Roubin, G. Giacometti, C. Hopf, et al.. Raman spectroscopy investigation of the H content of heated hard amorphous carbon layers. Diamond and Related Materials, 2013, 34, pp.100-104. ⟨10.1016/j.diamond.2013.02.009⟩. ⟨hal-00852738⟩