FABRICATION OF TWO-DIMENSIONAL PHOTONIC CRYSTALS WITH GE2SB2TE5 NANOHOLE ARRAYS BY NANOSPHERE LITHOGRAPHY

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1300-1305
Author(s):  
KI-HO SONG ◽  
HYUN-YONG LEE ◽  
HOE-YOUNG YANG ◽  
SUNG-WON KIM ◽  
JAE-HEE SEO ◽  
...  

Two-dimensional photonic crystals (2D-PCs) with Ge 2 Sb 2 Te 5 ( GST ) nanohole arrays were prepared by the nanosphere lithography (NSL) process. A primary factor of PCs is that the refractive index (n) and the n-modulation can be realized by using the GST films, which exhibit a reversible phase transformation between amorphous and crystalline states by laser illumination. The polystyrene (PS) spheres with a diameter of 500 nm were spin-coated on Si substrate and subsequently reduced by O 2-plasma treatment. The reduced spheres were utilized as a lift-off mask of the NSL process and their size and separation could be precisely controlled. Amorphous GST films were thermally evaporated and then the reduced PS spheres were removed. The fabricated GST nanohole arrays were observed by SEM and AFM. The nanohole diameters are nearly linearly reduced with increasing plasma-treatment time (t). The reduction rate (δ) for the conditions of this work was evaluated to be ~ 0.92 nm/s. The period (Λ) and filling factor (η) of PCs are structure parameters that determine their photonic bandgaps (PBGs). η-modulation can be easily achieved via a control of t and the Λ can be also modulated by the use of PS spheres with specific diameter. In addition, the PBGs for the fabricated GST 2 D PC were calculated by considering the amorphous and crystalline states of GST .

2012 ◽  
Vol 499 ◽  
pp. 90-94 ◽  
Author(s):  
Jin Yun Xu ◽  
Wen Yu Wang ◽  
Xin Jin

To improve the adhesion between ultra-high-molecular-weight polyethylene (UHMWPE) fibers and matrix, the UHMWPE fibers were treated by low temperature argon-plasma. The effects of argon-plasma treatment on the properties of UHMWPE have been investigated. The roughness and wetting ability were all found to increase significantly after modifications. The tensile strength of UHMWE fibers were decreased with the plasma treatment time. The optimum plasma treatment is 2min.The increasing of roughness and wetting ability of UHMWPE fiber are beneficial to the improvement the adhesion between UHMWPE fiber and matrix.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 580
Author(s):  
Chao-Ching Chiang ◽  
Philip Nathaniel Immanuel ◽  
Yi-Hsiung Chiu ◽  
Song-Jeng Huang

In this work we report on a rapid, easy-to-operate, lossless, room temperature heterogeneous H2O plasma treatment process for the bonding of poly(methyl methacrylate) (PMMA) and double-sided polished (DSP) silicon substrates by for utilization in sandwich structured microfluidic devices. The heterogeneous bonding of the sandwich structure produced by the H2O plasma is analyzed, and the effect of heterogeneous bonding of free radicals and high charge electrons (e−) in the formed plasma which causes a passivation phenomenon during the bonding process investigated. The PMMA and silicon surface treatments were performed at a constant radio frequency (RF) power and H2O flow rate. Changing plasma treatment time and powers for both processes were investigated during the experiments. The gas flow rate was controlled to cause ionization of plasma and the dissociation of water vapor from hydrogen (H) atoms and hydroxyl (OH) bonds, as confirmed by optical emission spectroscopy (OES). The OES results show the relative intensity peaks emitted by the OH radicals, H and oxygen (O). The free energy is proportional to the plasma treatment power and gas flow rate with H bonds forming between the adsorbed H2O and OH groups. The gas density generated saturated bonds at the interface, and the discharge energy that strengthened the OH-e− bonds. This method provides an ideal heterogeneous bonding technique which can be used to manufacture new types of microfluidic devices.


Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 991 ◽  
Author(s):  
Masoud Shekargoftar ◽  
Jana Jurmanová ◽  
Tomáš Homola

Organic-inorganic halide perovskite materials are considered excellent active layers in the fabrication of highly efficient and low-cost photovoltaic devices. This contribution demonstrates that rapid and low-temperature air-plasma treatment of mixed organic-inorganic halide perovskite film is a promising technique, controlling its opto-electrical surface properties by changing the ratio of organic-to-inorganic components. Plasma treatment of perovskite films was performed with high power-density (25 kW/m2 and 100 W/cm3) diffuse coplanar surface barrier discharge (DCSBD) at 70 °C in ambient air. The results show that short plasma treatment time (1 s, 2 s, and 5 s) led to a relatively enlargement of grain size, however, longer plasma treatment time (10 s and 20 s) led to an etching of the surface. The band-gap energy of the perovskite films was related to the duration of plasma treatment; short periods (≤5 s) led to a widening of the band gap from ~1.66 to 1.73 eV, while longer exposure (>5 s) led to a narrowing of the band gap to approx. 1.63 eV and fast degradation of the film due to etching. Surface analysis demonstrated that the film became homogeneous, with highly oriented crystals, after short plasma treatment; however, prolonging the plasma treatment led to morphological disorders and partial etching of the surface. The plasma treatment approach presented herein addresses important challenges in current perovskite solar cells: tuning the optoelectronic properties and manufacturing homogeneous perovskite films.


2006 ◽  
Vol 13 (02n03) ◽  
pp. 265-271
Author(s):  
CHI-AN DAI ◽  
TAI-AN TSUI ◽  
YAO-YI CHENG

The interface between biaxially oriented poly (ethylene terephthalate) (PET) films and poly (styrene-co-maleic anhydride) (PSMA) was reinforced by nitrogen plasma treatment of PET film and subsequent annealing treatment of the PET/PSMA bi-material. The fracture toughness, Gc, of the interface was quantitatively measured using an asymmetric double cantilever beam test (ADCB). X-ray photoelectron spectrometry (XPS) was used to measure the change in the surface composition of PET films upon plasma treatment and correlate the fracture toughness of the interface. The fracture energy of PET/PSMA interface is significantly enhanced by annealing the plasma treated PET with PSMA at a temperature greater than the glass transition temperature of PSMA (~ 120°C). At an annealing temperature of 150°C, Gc increases with increasing plasma treatment time and reaches a plateau value of ~ 100–120 J/m2, a two order of magnitude increase in Gc compared with that of samples annealed at 130°C. The enhancement of the adhesion is resulted from the in-situ formation of copolymers due to reaction between amine functional groups from the plasma treatment and anhydride groups from PSMA. For plasma treatment time < 10 s, scanning electron microscope (SEM) measurement show that the fracture surface is relatively smooth indicating an interfacial failure between PET/PSMA. With increasing plasma treatment time and therefore increasing the amount of nitrogen functional groups on PET surface, large plastic deformation takes place at the PET/PSMA interface. For treatment time ≥ 100–150 s, the PET/PSMA interface becomes stronger than PET bulk material and consequently crack deviates from the interface and the failure occurs within the PET film. The interlayer fracture energy of a biaxially oriented PET film can thus be quantitatively measured with a Gc value of roughly 120 J/m2.


Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 935 ◽  
Author(s):  
Jacek Tyczkowski ◽  
Hanna Kierzkowska-Pawlak ◽  
Jan Sielski ◽  
Iwona Krawczyk-Kłys

This paper proposed a kinetic model that can describe the changes in the adhesion properties of styrene–butadiene (SBS) block copolymer surfaces under the influence of low-temperature plasma treatment. As a measure of these changes, the peel strength of joints formed between the copolymer surface and the polyurethane adhesive was chosen. Five types of low-temperature low-pressure RF plasma, two inert plasmas (Ar and He), and three reactive plasmas (O2, CO2, and CCl4) were tested. It was found that for all these types of plasma, the peel strength with the plasma treatment time first increases rapidly reaching a maximum value, and then there is a visible decrease in peel strength, after which the peel strength increases again. This dependence of the peel strength on the plasma treatment time is very well described by the proposed model, which considers three processes: (1) the generation of radical states followed by the creation of functional groups involved in the adhesive bonding process, (2) the surface cross-linking that decreases the concentration of these functional groups, and (3) the formation of nano-roughness. The model analysis revealed differences between the action of reactive and inert plasmas in the SBS surface cross-linking mechanism and preferential etching process, as well as differences in the generation of radical states between the O2 plasma (electron process) and other plasmas tested (ionic processes).


1997 ◽  
Vol 476 ◽  
Author(s):  
Seoghyeong Lee ◽  
Jae-Yoon Yoo ◽  
Kyunghui Oh ◽  
Jong-Wan Park

AbstractThe effect of post plasma treatment on dielectric properties and reliability of fluorine doped silicon oxide (SiOF) films were investigated by measuring their C-V and I-V characteristics, XPS, AFM, and AES. The post plasma treatment of SiOF films was carried out in-situ at 300 °C in the deposition chamber. In this research, when the post plasma treatment time increased, we obtained the following results: (1) The etch rate of SiOF films decreased from 80Å/sec to 10Å/sec. (2) Surface roughness of the plasma treated SiOF films was increased due to the ion bombardment effect of the plasma. (3) The refractive index and relative dielectric constant increased from 1.391 to 1.461 and 3.14 to 3.9, respectively, due to the changes of surface chemistry by the post plasma treatment. (4) The leakage current density of SiOF films prepared by ECRCVD using SiF4 and O2 was less than 1 × 10−9A/cm2. (5) The breakdown field strength increased from 3.5 MV/cm to 8 MV/cm. (6) The thermal stability of the Cu/TiN/SiOF/Si system remained stable up to 600 °C.


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