Carbon-based materials, Fernando Lázaro Freire Jr. Physics Department, Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)

1. Carbon-based materials
Fernando Lázaro Freire Jr.
Physics Department, Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio)

2. Where PUC-Rio is located?

3. About 10,000 undergraduate and 2,000 graduate students
Ministry of Education carries out a quadrennial evaluation of graduate courses. In the last evaluation
(2017-20) the courses of the Science and Technology Center received the following grade (1-7):
7 _ Mathematics, Informatics, Physics, Mechanical Eng., Production Eng.
6 _ Electrical Eng., Civil Eng.
5 _ Chemistry, Chemistry Eng., Metrology

4. Protective Coatings and Nanomaterials Laboratory
STM UHV Omicron
XPS Thermo (Alpha 110) FEG-SEM JEOL
AFM + Raman ND-MDT
FTIR Bruker Alpha, Goniometer for contact angle measurements Ramé-Hart Instruments
AFM Veeco Nanoscope III
Nanoindenter Hysitron

5. - Diamond-like carbon films
- Multiwalled carbon nanotubes
- Single wall carbon nanotubes
- Graphene
- today (2D-materials)

6. What does our research on carbon-based materials has in common over these years?
Essentially, the same basic synthesis process: CVD (Chemical Vapor Deposition)

7. Science, 245 (1989) 841.
Motivation: Theory
Carbon atoms with sp3 hybridization

8. Superhard Materials:
C
B N
B4C
c-BN
-C3N4
diamond

9. PECVD: C6H12 – N2
Motivation: Experiment

10. Plasma Enhanced CVD

11. PECVD: CH4- N2

13. PECVD: CH4-N2 and CH4-NH3
The C K edge electron energy loss spectra

14. HRTEM and Z-contrast images of a CNx/ZrN
superlattice (λ = 4.5 nm). The electron
diffraction pattern is in the inset.
RBS spectrum of a CNx/ZrN superlattice (λ = 7.2 nm)
and Simulation (3) ZrN0.5 (6.8x1022 atoms/cm3);
C3N4 (1.63 x1023 atoms/cm3); 0.5 at. % of Ar.
Carbon K-edge NEXAFS spectra

15. Magnetic hard disk: road map
Mater. Sci. Eng. R 37 (2002) 129

17. PECVD: CH4 + CF4
0 10 20 30 40
70
80
90
100
Contact
angle
(degree)
F content (at.%)

18. - MEMS and NEMS
- nanotribology
- MEMS devices
Macro world
Nano World
Water, not necessarily in ice form, is a good lubricant in everyday life,
making it ‘‘slippery when wet.’’ It also acts as a lubricant in numerous
industrial and biological settings, where it keeps sliding surfaces apart
from each other and allows easy shearing.
Is it true at nanoscale?

20. Spray pyrolysis: Multiwalled carbon nanotubes

21. Carbon MWNT
HRTEM
Precursors: ferrocene and toluene (C7H8)
Temperature: 800oC
CN MWNT
HRTEM
Precursors: ferrocene and benzilamine (C7H9N)
Temperature: 850oC
ferrocene

22. Ni
CNx
10 nm
HRTEM
TEM image obtained with a JEOL
4000EX (David J. Smith ASU)

23. Ni(NO3)2 (s)
NiO
Functionalization with metal nanoparticles:
1) Dissociation of Ni(NO3)2 with MWNT for the synthesis of NiO
nanoparticles.
2) Nickel Oxide reduction in H2 atmosphere
+ H2O
NO2+O2
Ni(NO3)2
(solution)
NiO
2Ni(NO3)2 (s) 2 NiO(s) + 4 NO2(g) + O2(g)
+
Nanotubes
+
Nanotubes +
Nanotubes
Nanotubes

24. MWNT CNx nanotubes

25. A.J.R. Silva et al.- PRL 100, 176803 (2008)
Nitrogen doped carbon nanotubes

26. MWCNT grown by spray pyrolysis with 2.0 wt % of ferrocene
Toluene with 0.25 wt % of Triphenylphosphine

27. XPS and XRD: iron phosphite

28. XPS Raman

29. LPCVD (Low pressure – Chemical Vapor Deposition): single wall carbon nanotubes
Growth system of nanotubes by LPCVD, insert: the ampoule containing precursor liquid.

30. LPCVD:
-catalyst: powder iron nitrate III and MgO, reduced at 700oC by a H2 flow at 65 torr.
- base pressure: 3 x 10-5 torr .
- precursor flow of ethanol (SWNT) or Triethyl Borate or Triisopropil borate (B-doped SWNT) at 13 torr during
13 minutes.

31. Raman
from RBM:
diameter of 0.8-1.2 nm
TEM image
SWNT ~1nm
SWNT bundles

32. Mg3B2O6
BC2O
Raman XPS and DFT
B2O3
G+ upshift due to
charge transfer

33. CVD system used for graphene growth
- Precursor: methane
- Catalyst: copper foil
Graphene synthesis by LPCVD

34. PMMA 0,5 %
1 % 2 %
Optical microscopy
PU diluted in THF compared with PMMA: support layer

35. Fingers: Cr/Au 50 nm
Optical microscopy
Scale: 10 µm
Gas sensor: interdigitated circuit
Journal of Sensors (2019) Article ID 5492583

36. Raman transmittance
Graphene/PU

37. Conclusion: Graphene/PU sample shows
microwave attenuation in the X-band without
considerable phase shift, in comparison with the
pure PU sample. Therefore, graphene/PU can be
applied as microwave absorber with differential
features of light-weight, flexibility, transparency,
and cost-effectiveness
S21 phase of empty
waveguide, PU and
graphene/PU samples
S11 phase of empty
waveguide, PU and
graphene/PU samples

38. -100 -50 0 50 100 150 200 250 300 350
0
200
400
600
800
1000
Heating
t2
Growth
Temperature
(ºC)
Time (minutes)
Cooling
t1
STM image
Scheme illustrating the process for graphene growth on Ge by CVD

39. Ge (100) APCVD 500 Torr/ 910 oC/ CH4 + H2 + Ar /120 minutes
(a) Raman spectra of graphene
synthesis on Ge using different
CH4:H2 flow ratios.
(b) FWHM of the 2D-band and the
I2D/IG band’s intensity ratio as a
function of the CH4:H2 flow ratios
(c) FWHM of the 2D-band and the
ID/IG band’s intensity ratio as a
function of the CH4:H2 flow ratios.
Best choice for CH4/H2 flow was 0.01
I2D/IG = 4 and FWHM2D = 33 cm-1

40. 90 min CH4/H2= 0.01 180 min
SEM
Self-limited growth, as is the case of copper substrate

41. Ge (100) Ge (110)

42. (b) Plot of the 2D vs G-band positions for the graphene film. Coloured lines indicate the
E2D and EG relationship for strained undoped (biaxial-strain is represented by the blue line
and uniaxial strain by the black line), and unstrained p-doped (ε = 0, red line) graphene.
(c) (dI/dV)/(I/V) curve. The dotted line indicates the Fermi level (EF) and the blue arrow
indicates the position of the Dirac point (ED).
Ge (110)

43. Volume 497, 15 December 2019, 143779
(c) as-grown( d) after ten months stored in air.
Coloured lines indicate the E2D and EG relationship for strained undoped
(biaxial-strain is represented by the blue line and uniaxial strain by the black
line), and unstrained p-doped (ε = 0, red line) graphene.
a) as-grown( d) after ten months
stored in air.

44. Chemical Vapour Deposition (CVD)
Sulfur (1.5 g) was placed in a zone 17.5 cm upstream of the
MoO3 (3.2 mg); The furnace was further heated for 3 min
yielding a temperature of 700 °C in the center and 275 °C
17.5 cm upstream. The furnace was then held at
temperature for 5 min before being allowed to cool to room
temperature.

45. Optical microscopy and AFM profile (WS2)
6.7µm
AFM
Optical

46. Volume 535, 1 January 2021, 147685
PL

47. Our group at PUC-Rio
Prof. Fernando Lázaro Freire Jr.
Prof. Marcelo E. H. Maia da Costa
Pos-docs
Dr. Cesar A. D. Mendoza
Dr. Neileth J. S. Figueroa
Dr. André N. Barbosa
Dr. Shuai Zhang
PhD students
Ms. Thais C. V. Carvalho
Me. Rodrigo Gomes Costa

48. Financial support

49. Thank you for your attention

50. 0 1 2 3 4 5
6
8
10
12
Lateral
force
(nN)
ln (v)
 = 72o
 = 95o
 = 90o
   
v
F
m
F
F C
N
L ln

 



51. Graphene pristine as the sensor material
NO2 is a oxidizing agent: remove electrons from graphene
surface, increasing the number of holes (graphene is a p-
type semiconductor) and consequently increases the
conductivity (reduces the sheet resistance)
NH3 is a reducing agent: suply electrons to graphene
surface, decreasing the number of holes and consequently
increases the sheet resistance
G. C. Mastrapa, F. L. Freire Jr., Journal of Sensors (2019) , p. ID 5492583-7,

53. XPS
F = 35 at.%
F = 10 at.%

54. Thermal treatment: 1000 oC/1 hour in H2 atmosphere
Copper foil 25 μm thick/Sigma Aldrich
Electron-backscatter diffraction (EBSD) image
Dr. André Pinto LabNano_CBPF
A.N. Barbosa, N.J.S. Figueroa, C.D. Mendoza, A.L. Pinto,
F.L. Freire Jr.
Mater. Chem. Phys. 219 (2018) 189