Bulk and surface‐enhanced Raman spectroscopy of nitrogen‐doped ultrananocrystalline diamond films

Abstract

Ultrananocrystalline diamond films (UNCD) grown in an Ar‐rich microwave plasma with nitrogen gas added in amounts of 0–25% were studied by Raman spectroscopy using 514.5 and 413.1 nm laser excitation. Besides the Raman spectra of diamond, the first and second order Raman scattering of disordered graphite and polyacetylene were detected and analyzed for samples with different nitrogen content. With surface enhanced Raman scattering (SERS) a variety of surface vibrational modes was observed: (i) CHx stretching vibrations of sp3 and sp2 hybridized carbon in the range of 2800–3100 cm–1; (ii) the sp2 and sp1 hybridized CC(CN) stretching modes in the range of 1600–2300 cm–1; and (iii) lines in the range of 200–1250 cm–1 related to different kinds of vibrations of substituted aromatic rings. These results indicate that in N‐doped UNCD films the intergrain material is a well connected mixture of predominantly sp2 phase with some amount of sp1 phase of carbon and nitrogen that is suggested to provide high electrical conductivity. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Analysis of photoluminescence background of Raman spectra of carbon nanotips grown by plasma-enhanced chemical vapor deposition

“…35 The peak around 2120 cm −1 results from the presence of nitrogen and is assigned to C = N vibration modes of paracyanogenlike chains. 36 Additionally, the Raman spectrum ͑2͒ features another weak peak at about 2160 cm −1 , which is associated with C ϵ N triple bonds. 37 Compared with the Raman spectrum ͑1͒, the Raman spectrum ͑2͒ has a much stronger PL background.…”

Nanodiamond Photoemitters Based on Strong Narrow‐Band Luminescence from Silicon‐Vacancy Defects

“…[27] The PL and Raman spectra measured for the UNCD and MCD films in the range 500-800 nm are shown in Figure 2. The Raman spectrum for the UNCD film consists of five lines, indicating the presence of three carbon phases: [28] diamond (the peak at 1333 cm À1 ), amorphous carbon (1350 cm À1 and 1560 cm À1 ), and polyacetylene (1140 cm À1 and 1480 cm À1 ). The narrow diamond peak at 1333 cm À1 is the only feature present in the spectrum of the MCD sample.…”

Diamond Nanowires: Fabrication, Structure, Properties and Applications

“…The UNCD films were deposited on Si substrates in a microwave plasma CVD reactor in Ar/CH 4 /H 2 /N 2 mixtures [78]. Scanning electron microscopy (SEM) images show that the morphology of the UNCD film surface undergoes essential changes when 25 % of nitrogen is added in the gas mixture: wire-like structures appear along with diamond nano-grains.…”