Effects of fluorine incorporation on the structural and electrical properties of Diamond-like carbon

2015 ◽  
Vol 1734 ◽  
Author(s):  
Kento Nakanishi ◽  
Jun Otsuka ◽  
Masanori Hiratsuka ◽  
Chen Chung Du ◽  
Akira Shirakura ◽  
...  

ABSTRACTDiamond-like carbon (DLC) has widespread attention as a new material for its application to thin film solar cells and other semiconducting devices. DLC can be produced at a lower cost than amorphous silicon, which is utilized for solar cells today. However, the electrical properties of DLC are insufficient for this purpose because of many dangling bonds in DLC. To solve this problem, we investigated the effects of the fluorine incorporation on the structural and electrical properties of DLC.We prepared five kinds of fluorinated DLC (F-DLC) thin film with different amounts of fluorine. Films were deposited by the radio-frequency plasma enhanced chemical vapor deposition (RF-PECVD) method. C6H6 and C6HF5 were used as source gases. The total gas flow rate was constant and the gas flow rate ratio R (=C6H6 / (C6H6 + C6HF5)) was changed from 0 to 1 in 0.25 ratio steps. We also prepared nitrogen doped DLC (F-DLC) on p-Si using N2 gas as a doping gas to form nitrogen doped DLC (F-DLC) / p-Si heterojunction diodes.X-ray photoelectron spectroscopy (XPS) showed that fluorine concentration in the DLC films was controlled. Moreover, the XPS analysis of the C1s spectrum at R=2/4 showed the presence of CF bonding. At R=1, CF2 bonding was observed in addition to CF bonding. The sheet resistivity of the films changed from 3.07×1012 to 4.86×109 Ω. The minimum value was obtained at R=2/4. The current-voltage characteristics indicated that nitrogen doped F-DLC of 2/4 and p-Si heterojunction diode exhibited the best rectification characteristics and its energy conversion efficiency had been maximized. This is because of a decrease of dangling bonds density by ESR analysis and an increase of sp2 structures by Raman analysis. When the fluorine is over certain content, the sheet resistivity increases because chain structures become larger, which is due to the CF2 bonding in F-DLC prevents ring structures. Many C2F4 species were observed and it may become precursors of the chain structure domains, such as (CF2)n.In this study, we revealed effects of fluorine incorporation on DLC and succeeded in increasing its conductivity and improving rectification characteristics of DLC/ p-Si hetero-junction diodes. Our results indicate that DLC fluorination is effective for the semiconducting material, such as solar cell applications.

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1635
Author(s):  
Md. Akhtaruzzaman ◽  
Md. Shahiduzzaman ◽  
Nowshad Amin ◽  
Ghulam Muhammad ◽  
Mohammad Aminul Islam ◽  
...  

Tungsten disulfide (WS2) thin films were deposited on soda-lime glass (SLG) substrates using radio frequency (RF) magnetron sputtering at different Ar flow rates (3 to 7 sccm). The effect of Ar flow rates on the structural, morphology, and electrical properties of the WS2 thin films was investigated thoroughly. Structural analysis exhibited that all the as-grown films showed the highest peak at (101) plane corresponds to rhombohedral phase. The crystalline size of the film ranged from 11.2 to 35.6 nm, while dislocation density ranged from 7.8 × 1014 to 26.29 × 1015 lines/m2. All these findings indicate that as-grown WS2 films are induced with various degrees of defects, which were visible in the FESEM images. FESEM images also identified the distorted crystallographic structure for all the films except the film deposited at 5 sccm of Ar gas flow rate. EDX analysis found that all the films were having a sulfur deficit and suggested that WS2 thin film bears edge defects in its structure. Further, electrical analysis confirms that tailoring of structural defects in WS2 thin film can be possible by the varying Ar gas flow rates. All these findings articulate that Ar gas flow rate is one of the important process parameters in RF magnetron sputtering that could affect the morphology, electrical properties, and structural properties of WS2 thin film. Finally, the simulation study validates the experimental results and encourages the use of WS2 as a buffer layer of CdTe-based solar cells.


2011 ◽  
Vol 63 (6) ◽  
pp. 433-439 ◽  
Author(s):  
Mohammad Asaduzzaman Chowdhury ◽  
Dewan Muhammad Nuruzzaman ◽  
Khaled Khalil ◽  
Mohammad Lutfar Rahaman

MRS Advances ◽  
2016 ◽  
Vol 2 (29) ◽  
pp. 1533-1538 ◽  
Author(s):  
S. Ishihara ◽  
Y. Hibino ◽  
N. Sawamoto ◽  
T. Ohashi ◽  
K. Matsuura ◽  
...  

ABSTRACTMolybdenum disulfide (MoS2) thin films were fabricated by two-step chemical vapor deposition (CVD) using (t-C4H9)2S2 and the effects of temperature, gas flow rate, and atmosphere on the formation were investigated in order to achieve high-speed low-temperature MoS2 film formation. From the results of X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) investigations, it was confirmed that c-axis orientation of the pre-deposited Mo film has a significant involvement in the crystal orientation after the reaction low temperature sulfurization annealing and we successfully obtained 3 nm c-axis oriented MoS2 thin film. From the S/Mo ratios in the films, it was revealed that the sulfurization reaction proceeds faster with increase in the sulfurization temperature and the gas flow rate. Moreover, the sulfurization under the H2 atmosphere promotes decomposition reaction of (t-C4H9)2S2, which were confirmed by XPS and density functional theory (DFT) simulation.


2007 ◽  
Vol 56 (4) ◽  
pp. 2377
Author(s):  
Ma Guo-Jia ◽  
Liu Xi-Liang ◽  
Zhang Hua-Fang ◽  
Wu Hong-Chen ◽  
Peng Li-Ping ◽  
...  

2009 ◽  
Author(s):  
Zhe Kang ◽  
Weizhi Li ◽  
Yadong Jiang
Keyword(s):  
Gas Flow ◽  

2014 ◽  
Vol 970 ◽  
pp. 128-131
Author(s):  
Ong Wai Kit ◽  
Karim bin Deraman ◽  
Wan Nurulhuda Wan Shamsuri ◽  
Jackie Chen Keng Yik

Diamond like carbon (DLC) thin films were grown onto glass substrates by using direct current plasma enhance chemical vapour deposition (DC-PECVD) system. Films were deposited under fixed deposition pressure (4 x 10-1 Torr), substrate temperature (500°C) and deposition time (3 hours) but with different flow rate of precursor gas (methane, hydrogen and argon). The fabricated films were characterized by using x-ray diffraction (XRD) and atomic force microscopy (AFM). XRD has revealed that the DLC films were having amorphous phase as the XRD spectrum did not show any obvious sharp peak. From AFM, it was discovered that the precursor gas flow rate has inversely relationship with the grain size and surface roughness of films.


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