• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.31 no.1
• /
• pp.55-60
• /
• 2018

Transparent conductive thin films (TCFs) are essential materials for solar cells, organic light-emitting diodes, and display panels. Indium tin oxide (ITO) is one of the most widely used commercial materials to create TCFs'; however, new materials that can possibly replace ITO at a lower cost and/or those possessing mechanical flexibility are urgently needed. Silver nanowire (AgNW) is one of those promising materials, as it is less expensive and possesses superior mechanical flexibility as compared to ITO. We used AgNW and sol-gel ZnO to fabricate composite thin films by spray coating. We propose two spray-coating methods: the 'metal-organic chemical vapor deposition (MOCVD)/AgNW' method and the Mixture method. These two methods are expected to be commercialized for high-quality and low-cost products, respectively.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.203.2-203.2
• /
• 2013

Hydrothermally grown ZnO nanorods were synthesized with various Sn contents on quartz substrates, ranging from 0 to 2.5 at% in increment 0.5 at%. Scanning electron microscopy (SEM) and ultraviolet (UV)- visible spectroscopy were used to determine the effect of Sn doping on the structural and optical properties. In the SEM images, the nanorods have hexagonal wurzite structure and the diameter of the nanorods increase with increase in the Sn contents. The optical parameters of the Sn-doped ZnO nanorods such as the absorption coefficients, optical bandgaps, Urbach energies, refractive indices, dispersion parameters, dielectric constants, and optical conductivities were gained from the transmittance and reflectance results. In the PL spectra, the NBE peaks in the UV region decrease and blue-shift with increase in the Sn contents. In addition, the DLE peaks in the visible region of the nanorods shift toward low-energy region when the ZnO nanorods doped with various Sn contents.

• Journal of the Korean institute of surface engineering
• /
• v.47 no.6
• /
• pp.311-315
• /
• 2014

Indium tin oxide (ITO) thin films (30 nm) were deposited on PET substrate by reactive DC magnetron sputtering using In/Sn(2, 5 wt.%) metal alloy target without intentionally substrate heating during the deposition under different DC powers of 70 ~ 110 W. The electrical properties were estimated by Hall-effect measurements system. The resistivity of ITO thin film deposited using In/Sn (5 wt.%) metal alloy target at low DC power increased with increasing annealing time. However, they increased with increasing annealing time at high DC power. In the case of ITO (Sn 2 wt%), we can't find clear change in resistivity with increasing annealing time. However, carrier density and mobility showed difference behavior due to change of oxygen vacancy.

• Korean Journal of Metals and Materials
• /
• v.50 no.8
• /
• pp.557-562
• /
• 2012

Self-organized ruthenium (Ru) dots were fabricated by $400^{\circ}C$ RTA (rapid thermal annealing) and ALD (atomic layer deposition). The dots were produced under the $400^{\circ}C$ RTA conditions for 10, 30 and 60 seconds on all Si(100)/200 nm-SiO2, glass, and glass/fluorine-doped tin oxide (FTO) substrates. Electrical sheet resistance, and surface microstructure were examined using a 4-point probe and FE-SEM (field emission scanning electron microscopy). Ru dots were observed when a 30 nm-Ru layer on a Si(100)/200 nm-SiO2 substrate was annealed for 10, 30 and 60 seconds, whereas the dots were only observed on a glass substrate when a 50 nm-Ru layer was annealed on glass. For a glass/FTO substrate, RTA <30 seconds was needed for 30 nm Ru thick films. Those dots can increase the effective surface area for silicon and glass substrates by up to 5-44%, and by 300% for the FTO substrate with a < $20^{\circ}$ wetting angle.

• Korean Journal of Materials Research
• /
• v.28 no.12
• /
• pp.758-762
• /
• 2018

The transfer characteristics of zinc tin oxide(ZTO) on silicon dioxide($SiO_2$) thin film transistor generally depend on the electrical properties of gate insulators. $SiO_2$ thin films are prepared with argon gas flow rates of 25 sccm and 30 sccm. The rate of ionization of $SiO_2$(25 sccm) decreases more than that of $SiO_2$(30 sccm), and then the generation of electrons decreases and the conductivity of $SiO_2$(25 sccm) is low. Relatively, the conductivity of $SiO_2$(30 sccm) increases because of the high rate of ionization of argon gases. Therefore, the insulating performance of $SiO_2$(25 sccm) is superior to that of $SiO_2$(30 sccm) because of the high potential barrier of $SiO_2$(25 sccm). The $ZTO/SiO_2$ transistors are prepared to research the $CO_2$ gas sensitivity. The stability of the transistor of $ZTO/SiO_2$(25 sccm) as a high insulator is superior owing to the high potential barrier. It is confirmed that the electrical properties of the insulator in transistor devices is an important factor to detect gases.

• Journal of Electrochemical Science and Technology
• /
• v.10 no.1
• /
• pp.61-68
• /
• 2019

Well aligned $SnO_2$-doped ZnO nanorods were prepared by single step or 2-step electrochemical depositions in a mixture solution of zinc nitrate hexahydrate, ammonium hydroxide solution and 0.1 M tin chloride pentahydrate. The morphologies of electrochemically deposited $SnO_2$-doped ZnO were transformed from plain (or network) structures at low reduction potential to needles on hills at high reduction potential. Well aligned ZnO was prepared at intermediate potential ranges. Reduction reagent and a high concentration of Zn precursor were required to fabricate $SnO_2$ doped ZnO nanorods. When compared to results obtained by single step electrochemical deposition, 2-step electrochemical deposition produced a much higher density of nanorods, which was ascribed to less potential being required for nucleation of nanorods by the second-step electrochemical deposition because the surface was activated in the first-step. Mechanisms of $SnO_2$ doped ZnO nanorods prepared at single step or 2-step was described in terms of applied potential ranges and mass-/charge- limited transfer.

• Advances in nano research
• /
• v.7 no.1
• /
• pp.13-24
• /
• 2019

Well-crystalline $SnO_2$ nanoparticles of 4-5 nm size with different In contents were synthesized by hydrothermal process at relatively low temperature and characterized by transmission electron microscopy (TEM), microRaman spectroscopy and photoluminescence (PL) spectroscopy. Indium incorporation in $SnO_2$ lattice is seen to cause a lattice expansion, increasing the average size of the nanoparticles. The fundamental phonon vibration modes of $SnO_2$ lattice suffer a broadening, and surface modes associated to particle size shift gradually with the increase of In content. Incorporation of In drastically enhances the PL emission of $SnO_2$ nanoparticles associated to deep electronic defect levels. Although In incorporation reduces the band gap energy of $SnO_2$ crystallites only marginally, it affects drastically their dye degradation behaviors under UV illumination. While the UV degradation of methylene blue (MB) by undoped $SnO_2$ nanoparticles occurs through the production of intermediate byproducts such as azure A, azure B, and azure C, direct mineralization of MB takes place for In-doped $SnO_2$ nanoparticles.

• Korean Journal of Materials Research
• /
• v.29 no.4
• /
• pp.228-232
• /
• 2019

Copper electroplating and electrode patterning using a screen printer are applied instead of lithography for heterostructure with intrinsic thin layer(HIT) silicon solar cells. Samples are patterned on an indium tin oxide(ITO) layer using polymer resist printing. After polymer resist patterning, a Ni seed layer is deposited by sputtering. A Cu electrode is electroplated in a Cu bath consisting of $Cu_2SO_4$ and $H_2SO_4$ at a current density of $10mA/cm^2$. Copper electroplating electrodes using a screen printer are successfully implemented to a line width of about $80{\mu}m$. The contact resistance of the copper electrode is $0.89m{\Omega}{\cdot}cm^2$, measured using the transmission line method(TLM), and the sheet resistance of the copper electrode and ITO are $1{\Omega}/{\square}$ and $40{\Omega}/{\square}$, respectively. In this paper, a screen printer is used to form a solar cell electrode pattern, and a copper electrode is formed by electroplating instead of using a silver electrode to fabricate an efficient solar cell electrode at low cost.

• Korean Journal of Metals and Materials
• /
• v.46 no.1
• /
• pp.26-32
• /
• 2008

Examination of two bronze vessels supposedly from the Koryo dynasty revealed that they consist of bowls and stands that are fixed together using rivet joints made of Cu-Ag alloys. The bowls and stands were forged out of unleaded bronze alloys of approximately 22 weight % Sn before being quenched from the ${\alpha}+{\beta}$ region of the Cu-Sn phase diagram. This specific alloy and the thermo-mechanical treatment constitute two key elements of the unique technical tradition called Bangcha (방짜) that has long been established in Korea. The high Sn content ensures better casting and the thermal treatment causes the brittle ${\delta}$ phase to be avoided in forging as well as in services. The experiment on the laboratory Cu-Ag alloys of varying Ag contents suggested that the Cu-Ag system was the best choice of materials for the rivets at the time in view of their color, availability, ductility and low melting points.

• Current Photovoltaic Research
• /
• v.11 no.3
• /
• pp.96-102
• /
• 2023

Sn-Pb narrow-bandgap perovskite solar cells, which is a light-harvesting layer thicker than 1.3 micrometers, is needed to enhance the low photocurrent. The fabrication of such a thick film through solution processing is a key challenge. Here, we studied and characterized the film by using a precursor solution of increased concentration, comparing it with the universally used 1-micrometer Sn-Pb perovskite film. The increase in molar concentration clearly induced thickness enhancement, but we observed that it also created numerous voids at the interface with bottom charge transporting layer. We hypothesized that these voids might hinder the increase in photocurrent associated with thickness enhancement. By introducing methylammonium chloride (MACl), we successfully fabricated Sn-Pb perovskite film with a thickness of 1.3 micrometer and no voids. Void-controlled Sn-Pb perovskite solar cells not only demonstrated superior short-circuit current density compared to those with voids but also operated smoothly under light exposure.