论文部分内容阅读
Diamond like carbon (DLC) is a name first used by Aisenberg et al. [1] to introduce a group of amorphous carbon materials containing significant fraction of sp3 carbons as in diamond. DLC does not represent a specific structure it is rather a mixture of amorphous and crystalline carbon phases, with properties strongly depending on the deposition conditions. Because of their unique combination of properties such as optical transparency, high electrical resistivity, high hardness and chemical inertness, DLC films received a considerable interest in wide range of industrial application [2, 3].
Thermal annealing can change the structural, optical and electrical properties, reduce intrinsic compressive stress and increase graphitization [4, 5]. Thermal annealing of DLC films results in hydrogen loss, which occurs by breaking of C-H bonds in these films affecting film stability due to consequent bonding changes. Besides hydrogen losses process the sp2 content increase and finally, when sp2 clusters are large enough to overlap, the optical band gap will be close. Structural modification of DLC films due to thermal annealing can be studied using FTIR spectroscopy and Raman spectroscopy [4, 6]. The peak position, intensity and area are very depending on the structure of the DLC films.
In the current work we repot the effect of annealing process on the structural and optical properties of DLC films deposited by PECVD on amorphous glass substrate. The annealing process was performed in N2 atmosphere at different temperatures for 20 min. The effect has been has been observed by comparing the property before and after annealing.
of Origin 7 computer program. As deposited DLC films have band gap value of 3.3 eV as shown in Fig. 2. Annealing at temperature 300 shows an increase in the energy gap value up to 3.7, that could be as a result in a decrease in the defects of the films. No significant variation in the band gap value has been recorded up to 400 °C. While the hydrogen losses started at 300 °C, the optical energy gap variation not observed before 400 °C, which suggest that there is no direct relation between the hydrogen losses and the band gap. The observed decrease in the band gap value could be attributed due to the increase in the sp2 fraction in the DLC films. chemical vapor deposition as a deposition technique in order to study the effect of thermal annealing on the properties of the obtained films. Thickness, structural and optical measurements of as deposited and annealed films were measured to explore these effects. The film thickness shows a decrease upon annealing. FTIR measurement shows that the films contain an amount of hydrogen which shows a perfentiality to attach sp3 structure since no C-H bond related to sp2 structure has been recorded. The hydrogen content has been speculated using FT-IR spectra of the samples which shown a reduction in the hydrogen content upon annealing. The nature of the optical transition has been investigated according to direct forbidden transition which gives the best straight line. On the contrary of the H-content the band gap value show better stability and start too reduced at 400 °C, while H-losses started
[1] S. Aisenberg, R. Chobat, Ion-beam deposition of thin films of diamondlike carbon, J. Appl. Phys. 42 (1971) 2935.
[2] W.S. Choi, K. Kim, J. Yi, B. Hong, Diamond-like carbon protective anti-reflection coating for Si solar cell, Materials Letters 62 (2008) 577.
[3] Z. Panosyan, Low resistive diamond like carbon film development technique, Thin Solid Films 517 (2009) 5404.
[4] W. Choi, B. Hong, The effect of annealing on the properties of diamond-like carbon protective antireflection coatings, Renewable Energy 33 (2008) 226.
[5] H. Li, Annealing effect on the structure, mechanical and tribological properties of hydrogenated diamond-like carbon films, Thin Solid Films 515 (2006) 2153.
[6] M. Rusop, Effects of annealing temperature on the optical, bonding, structural and electrical properties of nitrogenated amorphous carbon thin films grown by surface wave microwave plasma chemical vapor deposition, J. Mater. Sci. 41 (2006) 537.
[7] M. Chiu, Thermal stability of Cr-doped diamond like carbin films synthesized by cathodic arc evaporaion, Thin Solid Films 476 (2005) 258.
[8] A. Akl, Influence of preparation conditions on the dispersion parameters of sprayed iron oxide thin films, Applied Surface Science 256 (2010) 7496.
[9] J. Pankovev, Optical processes in semiconductors, Dover Publications, New York, 1971.
[10] M.R. Roy, E. Pascual, M.C. Polo, Structural and optical properties of diamond like thin films deposited by asymmetric bipolar pulsed-DC reactive magnetron sputtering, Surface and Coating Technology 202 (2008) 2354.
[11] R. Paul, Hydrophobicity in DLC films prepared by electrodeposition technique, Applied Surface Science 255(2008) 1705.
[12] R. W?chter, A. Cordery, Effects of post-deposition annealing on different DLC films, Diamond and Related Materials 8 (1999) 504.
[13] A.M.M. Omer, Electrical conductivity improvement by iodine doping for diamond-like carbon thin-films deposited by microwave surface wave plasma CVD, Diamond and Related Materials 15 (2006) 645.
[14] H. Weidong, D. Ding, Z. Rujuan, Synthesis and characterization of Diamond-like carbon films deposited on Quartz substrates, Plasma Scince and Technology 6(2004) 2255.
[15] W.S. Choi, B. Hong, The effect of annealing on the properties of diamond-like carbon protective antireflection coatings, Renewable Energy 33 (2008) 226.
[16] E. Titusa, D.S. Misra, A.K. Sikder, Quantitative analysis of hydrogen in chemical vapor deposited diamond films, Diamond and Related Materials 14 (2005) 476.
[17] W.J. Wang, T.M. Wang, B.L. Chen, Hydrogen release from diamondlike carbon films due to thermal annealing in vacuum, Nuclear Instruments and Methods in Physics Research B 117 (1996) 140.
[18] J. Choi, S. Miyagawa, S. Nakao, Thermal stability of diamond-like carbon films deposited by plasma based ion implantation technique with bipolar pulses, Diamond and Related Materials 15 (2006) 948.
Thermal annealing can change the structural, optical and electrical properties, reduce intrinsic compressive stress and increase graphitization [4, 5]. Thermal annealing of DLC films results in hydrogen loss, which occurs by breaking of C-H bonds in these films affecting film stability due to consequent bonding changes. Besides hydrogen losses process the sp2 content increase and finally, when sp2 clusters are large enough to overlap, the optical band gap will be close. Structural modification of DLC films due to thermal annealing can be studied using FTIR spectroscopy and Raman spectroscopy [4, 6]. The peak position, intensity and area are very depending on the structure of the DLC films.
In the current work we repot the effect of annealing process on the structural and optical properties of DLC films deposited by PECVD on amorphous glass substrate. The annealing process was performed in N2 atmosphere at different temperatures for 20 min. The effect has been has been observed by comparing the property before and after annealing.
of Origin 7 computer program. As deposited DLC films have band gap value of 3.3 eV as shown in Fig. 2. Annealing at temperature 300 shows an increase in the energy gap value up to 3.7, that could be as a result in a decrease in the defects of the films. No significant variation in the band gap value has been recorded up to 400 °C. While the hydrogen losses started at 300 °C, the optical energy gap variation not observed before 400 °C, which suggest that there is no direct relation between the hydrogen losses and the band gap. The observed decrease in the band gap value could be attributed due to the increase in the sp2 fraction in the DLC films. chemical vapor deposition as a deposition technique in order to study the effect of thermal annealing on the properties of the obtained films. Thickness, structural and optical measurements of as deposited and annealed films were measured to explore these effects. The film thickness shows a decrease upon annealing. FTIR measurement shows that the films contain an amount of hydrogen which shows a perfentiality to attach sp3 structure since no C-H bond related to sp2 structure has been recorded. The hydrogen content has been speculated using FT-IR spectra of the samples which shown a reduction in the hydrogen content upon annealing. The nature of the optical transition has been investigated according to direct forbidden transition which gives the best straight line. On the contrary of the H-content the band gap value show better stability and start too reduced at 400 °C, while H-losses started
[1] S. Aisenberg, R. Chobat, Ion-beam deposition of thin films of diamondlike carbon, J. Appl. Phys. 42 (1971) 2935.
[2] W.S. Choi, K. Kim, J. Yi, B. Hong, Diamond-like carbon protective anti-reflection coating for Si solar cell, Materials Letters 62 (2008) 577.
[3] Z. Panosyan, Low resistive diamond like carbon film development technique, Thin Solid Films 517 (2009) 5404.
[4] W. Choi, B. Hong, The effect of annealing on the properties of diamond-like carbon protective antireflection coatings, Renewable Energy 33 (2008) 226.
[5] H. Li, Annealing effect on the structure, mechanical and tribological properties of hydrogenated diamond-like carbon films, Thin Solid Films 515 (2006) 2153.
[6] M. Rusop, Effects of annealing temperature on the optical, bonding, structural and electrical properties of nitrogenated amorphous carbon thin films grown by surface wave microwave plasma chemical vapor deposition, J. Mater. Sci. 41 (2006) 537.
[7] M. Chiu, Thermal stability of Cr-doped diamond like carbin films synthesized by cathodic arc evaporaion, Thin Solid Films 476 (2005) 258.
[8] A. Akl, Influence of preparation conditions on the dispersion parameters of sprayed iron oxide thin films, Applied Surface Science 256 (2010) 7496.
[9] J. Pankovev, Optical processes in semiconductors, Dover Publications, New York, 1971.
[10] M.R. Roy, E. Pascual, M.C. Polo, Structural and optical properties of diamond like thin films deposited by asymmetric bipolar pulsed-DC reactive magnetron sputtering, Surface and Coating Technology 202 (2008) 2354.
[11] R. Paul, Hydrophobicity in DLC films prepared by electrodeposition technique, Applied Surface Science 255(2008) 1705.
[12] R. W?chter, A. Cordery, Effects of post-deposition annealing on different DLC films, Diamond and Related Materials 8 (1999) 504.
[13] A.M.M. Omer, Electrical conductivity improvement by iodine doping for diamond-like carbon thin-films deposited by microwave surface wave plasma CVD, Diamond and Related Materials 15 (2006) 645.
[14] H. Weidong, D. Ding, Z. Rujuan, Synthesis and characterization of Diamond-like carbon films deposited on Quartz substrates, Plasma Scince and Technology 6(2004) 2255.
[15] W.S. Choi, B. Hong, The effect of annealing on the properties of diamond-like carbon protective antireflection coatings, Renewable Energy 33 (2008) 226.
[16] E. Titusa, D.S. Misra, A.K. Sikder, Quantitative analysis of hydrogen in chemical vapor deposited diamond films, Diamond and Related Materials 14 (2005) 476.
[17] W.J. Wang, T.M. Wang, B.L. Chen, Hydrogen release from diamondlike carbon films due to thermal annealing in vacuum, Nuclear Instruments and Methods in Physics Research B 117 (1996) 140.
[18] J. Choi, S. Miyagawa, S. Nakao, Thermal stability of diamond-like carbon films deposited by plasma based ion implantation technique with bipolar pulses, Diamond and Related Materials 15 (2006) 948.