The experimental results of the effect of the gas phase composition on nitrogen-doped nanostructured
diamond coatings synthesized in the glow discharge plasma on their structure and resistance have been
presented. It was shown that changes in the electrical conductivity of the nitrogen doped nanostructured
diamond coatings are primarily related to changes in the electrical conductivity of the grain boundaries
and did not to changes in the grain size of the diamond phase.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3518

Dudnik, S.F.

Gritsyna, V.I.

Koshevoi, K.I.

Opalev, O.A.

Reshetnyak, E.N.

Strel'nitskij, V.E.

Vasilenko, R.L.

Voyevodin, V.N.

Electronic Sumy State University Institutional Repository

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE  NANOMATERIALS: APPLICATIONS AND PROPERTIES Vol. 2 No 1, 01NTF21(3pp) (2013)   2304-1862/2013/2(1)01NTF21(3) 01NTF21-1  2013 Sumy State University The Effect of Gas Phase Composition on the Structural Characteristics and Resistivity of Nitrogen-doped Nanostructured Diamond Coatings  R.L. Vasilenko, V.N. Voyevodin,V.I. Gritsyna, S.F. Dudnik, K.I. Koshevoi, O.A. Opalev, E.N. Reshetnyak, V.E. Strel'nitskij*  National Science Centre “Kharkov Institute of Physics and Technology”, 1, Akademicheskaya Str., 61108 Kharkov, Ukraine  (Received 03 June 2013; published online 31 August 2013)  The experimental results of the effect of the gas phase composition on nitrogen-doped nanostructured diamond coatings synthesized in the glow discharge plasma on their structure and resistance have been presented. It was shown that changes in the electrical conductivity of the nitrogen doped nanostructured diamond coatings are primarily related to changes in the electrical conductivity of the grain boundaries and did not to changes in the grain size of the diamond phase.  Keywords: Diamond coating, Doping by nitrogen, Nanostructure, Resistivity, Composition of the gas phase.   PACS numbers: 81.05.Ug, 81.15.Gh                                                           * strelnitskij@kipt.kharkov.ua 1. INTRODUCTION  Nanocrystalline diamond film is considered as a new material with great potential use in the techniques, medicine and other fields [1]. It has been found that deposition of nanostructured diamond coatings by CVD-method in the presence of nitrogen resulted in appearing of significant electrical conductivity, which expands the fields of diamond nanocrystalline films possible application. Detail studies of such coatings have shown that electrical conductivity of nitrogen-doped nanostructured diamond films related to the effects of nitrogen on the conductivity of grain boundaries consisting mainly of sp2-hybridized carbon atoms or other non-diamond forms of carbon, whose percentage in the volume of nanostructured diamond films can be up to 10%. Accordingly, the conductivity of diamond coatings must depend on the proportion of grain boundaries per unit volume of the diamond film, i.e. the grain size and the value of electrical conductivity of grain boundary layers themselves. In this connection it is of interest to perform studies of the effect of the gas phase composition at synthesis of nanostructured nitrogen doped diamond films on their structural characteristics and the value of their resistivity. This was the aim of this work.  2. EXPERIMENTAL  Diamond coatings synthesized from a gas mixture of hydrogen, methane, argon and nitrogen in DC glow discharge plasma stabilized by magnetic field. The concentration of nitrogen in the gas mixture can vary from 0 vol. % up to 38 vol. %, argon from 50 vol. % up to 75 vol.%, hydrogen from 0 vol. % up to 38 vol. %. The concentration of methane in the gas phase remained unchanged and was of 2 vol. %. The equipment used for synthesis of nitrogen doped nanocrystalline diamond coatings did not differ from those given in [2]. According to X-ray phase analysis in all coatings synthesized within this study, regardless of the composition of the gas phase used for the coating deposition, it was formed the polycrystalline diamond (cubic Fm3m space group symmetry). Due to the relatively small thickness of the films (4-10 microns) in the most part of X-ray spectra have been registered only the first two of the most intense reflection of diamond – (111) and (220) whose intensity increases with increasing film thickness. The typical X-ray spectra of the films shown in Fig. 1.  10 20 30 40 50 60 70 80 90 1002, degreeIntensity, arb. unitsG (002)G (100)Si D (311)D (220)D (111)  Fig. 1 – X-ray diffraction pattern of the nanocrystalline diamond film on a silicon substrate, arrows indicate the position of the diffraction peaks of diamond (D) and graphite (G)  In addition to the diamond peaks on some diffraction patterns revealed very weak lines at the angles 2 close to 25 and 42 degrees that may belong to the non-diamond forms of carbon most likely to graphite [3]. In addition, the halo was present at angle approximately of 20 degrees due to the presence of  X-ray amorphous phase which we could not identified. By the angular positions of the diffraction peaks it was calculated the lattice parameter of diamond films. The values obtained were in the range (0,3545-0,3557) nm, which is slightly smaller than the tabular values for natural diamond (a  0.3567 nm). The size of the coherent scattering region (CSR) for the studied films did not exceed 40 nm and depended on the deposition  R.L. VASILENKO, V.N. VOYEVODIN, V.I. GRITSYNA, ET AL. PROC. NAP 2, 01NTF21 (2013)   01NTF21-2 parameters of diamond coatings. On Fig. 2a it was shown the data on size of CSR value for nanocrystalline diamond coatings synthesized in gas mixtures containing argon of 60 vol. %,  methane of 2 vol. %, and different concentrations of nitrogen CN and hydrogen. On Fig. 3 it was shown the scanned electron images of the samples surface. From these figures it can be seen that increasing the nitrogen concentration in the gas mixture generally leads to reduction the size of structural elements in electron microscopic images and decreasing the CSR value in comparison with the film which was deposited without nitrogen (0 % N2). Such behaviour with increasing the nitrogen concentration is non-monotonic. In the range of nitrogen concentration of  6-19 vol. % the structural elements rather increased, the size of the CSR increased from 20 to 25 nm. With further increase of the nitrogen concentration in the gas mixture the structural elements take the form of an elongate needle, and the average CSR value reduced to 10 nm. In Fig. 2b it has been shown the data on resistivity of diamond coatings n synthesized from a gas mixture with different nitrogen concentrations. It can be seen that at decrease of CSR size in several times the resistance of diamond coatings decreased by more than three orders of magnitude with an increase of the nitrogen concentration in the gas phase. It is known that the grain size and structure of the diamond coatings are very dependent on the concentration of argon in the gas mixture [4]. In this regard, the experiments were performed at constant concentration of nitrogen in the gas mixture that was of 19 vol. % and different argon and hydrogen concentration, respectively. In Fig. 4a it was shown the dependence of CSR size of diamond coatings and on Fig. 4b the dependence of the diamond coatings resistivity on the concentration of argon CAr for the same series of samples. 0 10 20 30 40010203040% N2CSR, nm  0 10 20 30 4034567% N2log n, cm   Fig. 2 – The dependence of CSR size and resistivity n for nanocrystalline diamond films on the concentration of nitrogen in the gas mixture containing argon of 60 vol. %, methane of 2 vol. % and hydrogen (38 % – CN %) vol. %: a – CSR size; b – resistivity                Fig. 3 – The microstructure of the diamond coatings surface deposited in a gas mixture of argon of 60 vol. %, methane of 2 vol/ %, hydrogen of (38 %-CN %) vol/ % and nitrogen: a – 0 vol. %; b – 13 vol. %; с – 19  vol. %; d – 25 vol. %; e – 32 vol. %; f – 38 vol. %  a b b c a d e f  THE EFFECT OF GAS PHASE COMPOSITION ON THE STRUCTURAL CHARACTERISTICS… PROC. NAP 2, 01NTF21 (2013)   01NTF21-3 45 50 55 60 65 70 75 800102030CSR, nm%Ar   45 50 55 60 65 70 75 8034567log n, cm % Ar   Fig. 4 – The dependence of CSR size and resistivity n for nanocrystalline diamond films on the concentration of argon in the gas mixture containing nitrogen of 19 vol. %, methane of 2 vol % and hydrogen (79 % – CAr %) vol. %: a – CSR size;  b – resistivity  Comparison of the data in Fig. 4a and Fig. 4b shows that in this case the change of the resistance and CSR size in investigated diamond films generally occurred in opposite directions  3. CONCLUSIONS  The data obtained on the value of the nanostructured diamond coatings resistance and the value of their CSR size indicates that changes in the electrical conductivity of nanostructured diamond films doped with nitrogen are related primarily to changes in the electrical conductivity of the grain boundaries, but not with the size of the diamond phase grains.  REFERENCES  1. O.A. Williams, Diamond Related Mater. 20, 621 (2011). 2. V.I. Gritsina, S.F. Dudnik, K.I. Koshevoi, O.A. Opalev, V.E. Strel’nitskij, Physical surface engineering 10(№4), 308 (2012). [In Russian]. 3. A.F. Azevedo, S.C. Ramos, M.R. Baldan, N.G. Ferreira, Diamond Related Mater. 17, 1137 (2008). 4. T. Lin, G.Y. Yu, A.T.S. Wee, Z.X. Shen Kian Ping Loh, Appl. Phys. Lett. 77, 2692 (2000).  b a 

The Effect of Gas Phase Composition on the Structural Characteristics and Resistivity of Nitrogen-doped Nanostructured Diamond Coatings

SocioEconomic Challenges Journal (Sumy State University)

PROCEEDINGS OF THE INTERNATIONAL CONFERENCE  
NANOMATERIALS: APPLICATIONS AND PROPERTIES 
Vol. 2 No 1, 01NTF21(3pp) (2013) 
 
 
2304-1862/2013/2(1)01NTF21(3) 01NTF21-1  2013 Sumy State University 
The Effect of Gas Phase Composition on the Structural Characteristics and Resistivity of 
Nitrogen-doped Nanostructured Diamond Coatings 
 
R.L. Vasilenko, V.N. Voyevodin,V.I. Gritsyna, S.F. Dudnik, K.I. Koshevoi, O.A. Opalev, 
E.N. Reshetnyak, V.E. Strel'nitskij* 
 
National Science Centre “Kharkov Institute of Physics and Technology”, 
1, Akademicheskaya Str., 61108 Kharkov, Ukraine 
 
(Received 03 June 2013; published online 31 August 2013) 
 
The experimental results of the effect of the gas phase composition on nitrogen-doped nanostructured 
diamond coatings synthesized in the glow discharge plasma on their structure and resistance have been 
presented. It was shown that changes in the electrical conductivity of the nitrogen doped nanostructured 
diamond coatings are primarily related to changes in the electrical conductivity of the grain boundaries 
and did not to changes in the grain size of the diamond phase. 
 
Keywords: Diamond coating, Doping by nitrogen, Nanostructure, Resistivity, Composition of the gas phase. 
 
 PACS numbers: 81.05.Ug, 81.15.Gh 
 
 
                                                        
* strelnitskij@kipt.kharkov.ua 
1. INTRODUCTION 
 
Nanocrystalline diamond film is considered as a 
new material with great potential use in the 
techniques, medicine and other fields [1]. It has been 
found that deposition of nanostructured diamond 
coatings by CVD-method in the presence of nitrogen 
resulted in appearing of significant electrical 
conductivity, which expands the fields of diamond 
nanocrystalline films possible application. Detail 
studies of such coatings have shown that electrical 
conductivity of nitrogen-doped nanostructured diamond 
films related to the effects of nitrogen on the 
conductivity of grain boundaries consisting mainly of 
sp2-hybridized carbon atoms or other non-diamond 
forms of carbon, whose percentage in the volume of 
nanostructured diamond films can be up to 10%. 
Accordingly, the conductivity of diamond coatings must 
depend on the proportion of grain boundaries per unit 
volume of the diamond film, i.e. the grain size and the 
value of electrical conductivity of grain boundary layers 
themselves. 
In this connection it is of interest to perform studies 
of the effect of the gas phase composition at synthesis 
of nanostructured nitrogen doped diamond films on 
their structural characteristics and the value of their 
resistivity. This was the aim of this work. 
 
2. EXPERIMENTAL 
 
Diamond coatings synthesized from a gas mixture 
of hydrogen, methane, argon and nitrogen in DC glow 
discharge plasma stabilized by magnetic field. The 
concentration of nitrogen in the gas mixture can vary 
from 0 vol. % up to 38 vol. %, argon from 50 vol. % up to 
75 vol.%, hydrogen from 0 vol. % up to 38 vol. %. The 
concentration of methane in the gas phase remained 
unchanged and was of 2 vol. %. The equipment used for 
synthesis of nitrogen doped nanocrystalline diamond 
coatings did not differ from those given in [2]. 
According to X-ray phase analysis in all coatings 
synthesized within this study, regardless of the 
composition of the gas phase used for the coating 
deposition, it was formed the polycrystalline diamond 
(cubic Fm3m space group symmetry). Due to the 
relatively small thickness of the films (4-10 microns) in 
the most part of X-ray spectra have been registered 
only the first two of the most intense reflection of 
diamond – (111) and (220) whose intensity increases 
with increasing film thickness. The typical X-ray 
spectra of the films shown in Fig. 1. 
 
10 20 30 40 50 60 70 80 90 100
2, degree
In
te
n
si
ty
, 
a
rb
. 
u
n
it
s
G
 (
0
0
2
)
G
 (
1
0
0
)
S
i 
D
 (
3
1
1
)
D
 (
2
2
0
)
D
 (
1
1
1
)
 
 
Fig. 1 – X-ray diffraction pattern of the nanocrystalline 
diamond film on a silicon substrate, arrows indicate the position 
of the diffraction peaks of diamond (D) and graphite (G) 
 
In addition to the diamond peaks on some 
diffraction patterns revealed very weak lines at the 
angles 2 close to 25 and 42 degrees that may belong to 
the non-diamond forms of carbon most likely to 
graphite [3]. In addition, the halo was present at angle 
approximately of 20 degrees due to the presence of  
X-ray amorphous phase which we could not identified. 
By the angular positions of the diffraction peaks it was 
calculated the lattice parameter of diamond films. The 
values obtained were in the range (0,3545-0,3557) nm, 
which is slightly smaller than the tabular values for 
natural diamond (a  0.3567 nm). The size of the 
coherent scattering region (CSR) for the studied films 
did not exceed 40 nm and depended on the deposition 
 R.L. VASILENKO, V.N. VOYEVODIN, V.I. GRITSYNA, ET AL. PROC. NAP 2, 01NTF21 (2013) 
 
 
01NTF21-2 
parameters of diamond coatings. 
On Fig. 2a it was shown the data on size of CSR 
value for nanocrystalline diamond coatings synthesized 
in gas mixtures containing argon of 60 vol. %,  methane 
of 2 vol. %, and different concentrations of nitrogen CN 
and hydrogen. On Fig. 3 it was shown the scanned 
electron images of the samples surface. 
From these figures it can be seen that increasing 
the nitrogen concentration in the gas mixture generally 
leads to reduction the size of structural elements in 
electron microscopic images and decreasing the CSR 
value in comparison with the film which was deposited 
without nitrogen (0 % N2). Such behaviour with 
increasing the nitrogen concentration is non-
monotonic. In the range of nitrogen concentration of  
6-19 vol. % the structural elements rather increased, 
the size of the CSR increased from 20 to 25 nm. With 
further increase of the nitrogen concentration in the 
gas mixture the structural elements take the form of 
an elongate needle, and the average CSR value reduced 
to 10 nm. In Fig. 2b it has been shown the data on 
resistivity of diamond coatings n synthesized from a 
gas mixture with different nitrogen concentrations. 
It can be seen that at decrease of CSR size in 
several times the resistance of diamond coatings 
decreased by more than three orders of magnitude with 
an increase of the nitrogen concentration in the gas 
phase. 
It is known that the grain size and structure of the 
diamond coatings are very dependent on the 
concentration of argon in the gas mixture [4]. In this 
regard, the experiments were performed at constant 
concentration of nitrogen in the gas mixture that was of 
19 vol. % and different argon and hydrogen concentration, 
respectively. In Fig. 4a it was shown the dependence of 
CSR size of diamond coatings and on Fig. 4b the 
dependence of the diamond coatings resistivity on the 
concentration of argon CAr for the same series of samples. 
0 10 20 30 40
0
10
20
30
40
% N
2
C
S
R
, 
n
m
 
 
0 10 20 30 40
3
4
5
6
7
% N
2
lo
g
 
n
, 

c
m
 
 
 
Fig. 2 – The dependence of CSR size and resistivity n for 
nanocrystalline diamond films on the concentration of 
nitrogen in the gas mixture containing argon of 60 vol. %, 
methane of 2 vol. % and hydrogen (38 % – CN %) vol. %: a – 
CSR size; b – resistivity 
 
 
   
   
   
   
 
Fig. 3 – The microstructure of the diamond coatings surface deposited in a gas mixture of argon of 60 vol. %, methane of 2 vol/ %, 
hydrogen of (38 %-CN %) vol/ % and nitrogen: a – 0 vol. %; b – 13 vol. %; с – 19  vol. %; d – 25 vol. %; e – 32 vol. %; f – 38 vol. % 
 
a 
b 
b c a 
d e f 
 THE EFFECT OF GAS PHASE COMPOSITION ON THE STRUCTURAL CHARACTERISTICS… PROC. NAP 2, 01NTF21 (2013) 
 
 
01NTF21-3 
45 50 55 60 65 70 75 80
0
10
20
30
C
S
R
, 
n
m
%Ar  
 
45 50 55 60 65 70 75 80
3
4
5
6
7
lo
g
 
n
, 

c
m
 
% Ar  
 
Fig. 4 – The dependence of CSR size and resistivity n for 
nanocrystalline diamond films on the concentration of argon 
in the gas mixture containing nitrogen of 19 vol. %, methane 
of 2 vol % and hydrogen (79 % – CAr %) vol. %: a – CSR size;  
b – resistivity 
 
Comparison of the data in Fig. 4a and Fig. 4b shows 
that in this case the change of the resistance and CSR 
size in investigated diamond films generally occurred 
in opposite directions 
 
3. CONCLUSIONS 
 
The data obtained on the value of the 
nanostructured diamond coatings resistance and the 
value of their CSR size indicates that changes in the 
electrical conductivity of nanostructured diamond films 
doped with nitrogen are related primarily to changes in 
the electrical conductivity of the grain boundaries, but 
not with the size of the diamond phase grains.
 
 
REFERENCES 
 
1. O.A. Williams, Diamond Related Mater. 20, 621 (2011). 
2. V.I. Gritsina, S.F. Dudnik, K.I. Koshevoi, O.A. Opalev, 
V.E. Strel’nitskij, Physical surface engineering 10(№4), 
308 (2012). [In Russian]. 
3. A.F. Azevedo, S.C. Ramos, M.R. Baldan, N.G. Ferreira, 
Diamond Related Mater. 17, 1137 (2008). 
4. T. Lin, G.Y. Yu, A.T.S. Wee, Z.X. Shen Kian Ping Loh, 
Appl. Phys. Lett. 77, 2692 (2000). 
 
b 
a 


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The Effect of Gas Phase Composition on the Structural Characteristics and Resistivity of Nitrogen-doped Nanostructured Diamond Coatings

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