FABRICATION OF CARBON THIN FILMS BY PULSED LASER DEPOSITION IN DIFFERENT AMBIENT ENVIRONMENTS

2016 ◽  
Vol 78 (3) ◽  
Author(s):  
Mohamad Helmi Abd Mubin ◽  
Muhammad Sufi Roslan ◽  
Syed Zuhaib Haider Rizvi ◽  
Kashif Chaudhary ◽  
Suzairi Daud ◽  
...  

In this work, carbon thin films are grown in different background environments (Air, Helium and Argon) at different pressures (60, 160, 500 and 1000 mbar) by ablating the graphite target with Nd:YAG laser of wavelength of 1064 nm, pulse energy of 740 mJ and pulse rate of 6 ns. 10,000 laser shots are used to ablate graphite target under different ambient conditions. Grown thin films are analyzed by Atomic Force Microscopy (AFM) to measure thickness, roughness average, maximum profile peak height, average maximum height of profile and spacing ratio of the surface. The obtained results show that the roughness average, thickness of film, maximum profile peak height, average maximum height of profile and spacing ratio of thin films decreases with increase in ambient pressuresand shows highest value at low pressure (160 mbar) in helium environment as compared with air and argon.

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ronak Rahimi ◽  
V. Narang ◽  
D. Korakakis

PTCDI-C8 due to its relatively high photosensitivity and high electron mobility has attracted much attention in organic semiconductor devices. In this work, thin films of PTCDI-C8 with different thicknesses were deposited on silicon substrates with native silicon dioxide using a vacuum thermal evaporator. Several material characterization techniques have been utilized to evaluate the structure, morphology, and optical properties of these films. Their optical constants (refractive index and extinction coefficient) have been extracted from the spectroscopic ellipsometry (SE). X-ray reflectivity (XRR) and atomic force microscopy (AFM) were employed to determine the morphology and structure as well as the thickness and roughness of the PTCDI-C8 thin films. These films revealed a high degree of structural ordering within the layers. All the experimental measurements were performed under ambient conditions. PTCDI-C8 films have shown to endure ambient condition which allows pots-deposition characterization.


2006 ◽  
Vol 965 ◽  
Author(s):  
Harald Graaf ◽  
Christine C Mattheus ◽  
Derck Schlettwein

ABSTRACTThe aromatic core of perylene bisimides can be twisted by chemical substitution with chlorine in the bay-position. An example for this strategy is 1,6,7,10-tetra-chloro-N,N'-dimethyl-perylene-tetracarboxylic-bisimide, Cl4MePTCDI. This twisting leads to a decrease in directed intermolecular interactions, which causes a decrease in the electronic coupling of the molecules, interesting to be investigated in thin films of this molecular semiconductor. An amorphous solid phase was formed by physical vapor deposition. This amorphous phase showed the tendency to crystallize under ambient conditions as apparent von optical microscopy at the films. The crystallized phase was investigated by atomic force microscopy AFM and optical methods, where a formation of weak excimers was found.


1999 ◽  
Vol 353 (1-2) ◽  
pp. 194-200 ◽  
Author(s):  
C. Coupeau ◽  
J.F. Naud ◽  
F. Cleymand ◽  
P. Goudeau ◽  
J. Grilhé

2018 ◽  
Vol 5 (2) ◽  
pp. 171179 ◽  
Author(s):  
Bramaramba Gnapareddy ◽  
Sreekantha Reddy Dugasani ◽  
Junyoung Son ◽  
Sung Ha Park

DNA is considered as a useful building bio-material, and it serves as an efficient template to align functionalized nanomaterials. Riboflavin (RF)-doped synthetic double-crossover DNA (DX-DNA) lattices and natural salmon DNA (SDNA) thin films were constructed using substrate-assisted growth and drop-casting methods, respectively, and their topological, chemical and electro-optical characteristics were evaluated. The critical doping concentrations of RF ([RF] C , approx. 5 mM) at given concentrations of DX-DNA and SDNA were obtained by observing the phase transition (from crystalline to amorphous structures) of DX-DNA and precipitation of SDNA in solution above [RF] C . [RF] C are verified by analysing the atomic force microscopy images for DX-DNA and current, absorbance and photoluminescence (PL) for SDNA. We study the physical characteristics of RF-embedded SDNA thin films, using the Fourier transform infrared spectrum to understand the interaction between the RF and DNA molecules, current to evaluate the conductance, absorption to understand the RF binding to the DNA and PL to analyse the energy transfer between the RF and DNA. The current and UV absorption band of SDNA thin films decrease up to [RF] C followed by an increase above [RF] C . By contrast, the PL intensity illustrates the reverse trend, as compared to the current and UV absorption behaviour as a function of the varying [RF]. Owing to the intense PL characteristic of RF, the DNA lattices and thin films with RF might offer immense potential to develop efficient bio-sensors and useful bio-photonic devices.


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