Sb-doped SnO2 (ATO) transparent conducting films are fabricated using horizontal ultrasonic spray pyrolysis deposition (HUSPD) to form uniform and compact film structures with homogeneously supplied precursor solution. To optimize the molar concentration and transparent conducting performance of the ATO films using HUSPD, we use precursor solutions of 0.15, 0.20, 0.25, and 0.30 M. As the molar concentration increases, the resultant ATO films exhibit more compact surface structures because of the larger crystallite sizes and higher ATO crystallinity because of the greater thickness from the accelerated growth of ATO. Thus, the ATO films prepared at 0.25 M have the best transparent conducting performance (12.60±0.21 Ω/□ sheet resistance and 80.83% optical transmittance) and the highest figure-of-merit value (9.44±0.17 × 10-3 Ω-1). The improvement in transparent conducting performance is attributed to the enhanced carrier concentration by the improved ATO crystallinity and Hall mobility with the compact surface structure and preferred (211) orientation, ascribed to the accelerated growth of ATO at the optimized molar concentration. Therefore, ATO films fabricated using HUSPD are transparent conducting film candidates for optoelectronic devices.

ZnMgBeGaO/Ag/ZnMgBeGaO multilayer structures were sputter grown and characterized in detail. Results indicated that the electrical properties of the ZnMgBeGaO films were significantly improved by inserting an Ag layer with proper thickness (~ 10 nm). Structures with thicker Ag films showed much lower optical transmission, although the electrical conductivity was further improved. It was also observed that the electrical properties of the multilayer structure were sizably improved by annealing in vacuum (~35% at 300 oC). The optimum ZnMgBeGaO(20nm)/Ag(10nm)/ZnMgBeGaO(20nm) structure exhibited an electrical resistivity of ~2.6 × 10−5 Ωcm (after annealing), energy bandgap of ~3.75 eV, and optical transmittance of 65%~ 95 % over the visible wavelength range, representing a significant improvement in characteristics versus previously reported transparent conductive materials.

A metal mesh TCE film is fabricated using a series of processes such as UV imprinting of a transparent trench pattern (with a width of 2-5 μm) onto a PET film, filling it with silver paste, wiping of the surface, and heatcuring the silver paste. In this work nanosized (40-50 nm) silver particles are synthesized and mixed with submicron (250-300 nm)-sized silver particles to prepare silver paste for the fabrication of metal mesh-type TCE films. The filling of these silver pastes into the patterned trench layer is examined using a specially designed filling machine and the rheological testing of the silver pastes. The wiping of the trench layer surface to remove any residual silver paste or particles is tested with various mixture solvents, and ethyl cellosolve acetate (ECA):DI water = 90:10 wt% is found to give the best result. The silver paste with 40-50 nm Ag:250-300 nm Ag in a 10:90 wt% mixture gives the highest electrical conductance. The metal mesh TCE film obtained with this silver paste in an optimized process exhibits a light transmittance of 90.4% and haze at 1.2%, which is suitable for TSP application.

In this study, we report a general method for preparation of a one-dimensional (1D) arrangement of Au nanoparticles on single-walled carbon nanotubes (SWNTs) using biologically programmed peptides as structure-guiding 1D templates. The peptides were designed by the combination of glutamic acid (E), glycine (G), and phenylalanine (F) amino acids; peptides efficiently debundled and exfoliated the SWNTs for stability of the dispersion and guided the growth of the array of Au nanoparticles in a controllable manner. Moreover, we demonstrated the superior ability of 1D nanohybrids as flexible, transparent, and conducting materials. The highly stable dispersion of 1D nanohybrids in aqueous solution enabled the fabrication of flexible, transparent, and conductive nanohybrid films using vacuum filtration, resulting in good optical and electrical properties.

목 적: 본 연구는 SnO2를 모체로 하는 투명전도성 박막을 제조하기 위하여, 가용성 염인 Sn-Chloride와 H3PO4를 출발물질로 사용하였으며, 졸-겔법으로 박막을 제조하여 특성평가를 연구함이다. 방 법: Spin coating기를 이용하여 코팅용액을 기판에 떨어뜨린 후 공기분위기에서 2000 rpm으로 10초간 기판을 회전하여 박막을 도포하며, 500℃로 10분간 열처리하여 P-doped SnO2 박막을 제조하였다. 결 과: 박막의 표면에는 코팅 횟수가 5회, 10회의 경우에는 기공이나 크랙이 나타나지 않았으나 15회 및 20회로 증가함에 따라 미세한 기공들이 관찰되었다. 가시영역에서의 투과율은 5회 및 10회 코팅한 박막의 경우 약 85~90%을 나타내고 있으나, 코팅횟수가 15회 및 20회로 증가함에 따라 박막의 투과율은 80% 이하로 급격히 감소하였다. 4-probe법을 이용한 전기저항은 박막의 코팅횟수가 10회일 경우에 2.7×10-4Ω·cm-1이었으며, 코팅회수가 15회 및 20회로 증가함에 따라 9.8×10-3Ω?cm-1 및 8.3×10-2Ω·cm-1으로 박막의 저항값은 급격히 증가하였다. 결 론: 10회 코팅한 박막의 가시영역에서의 투과율은 85~90%로 매우 높았으며, 저항 값은 2.7×10-4Ω?cm-1로 투명 전도막으로 사용하기에 충분한 특성을 나타냈다.

Transparent and conducting thin films of Ta-doped SnO2 were fabricated on a glass substrate by a pulse laserdeposition(PLD) method. The structural, optical, and electrical properties of these films were investigated as a function ofdoping level, oxygen partial pressure, substrate temperature, and film thickness. XRD results revealed that all the deposited filmswere polycrystalline and the intensity of the (211) plane of SnO2 decreased with an increase of Ta content. However, theorientation of the films changed from (211) to (110) with an increase in oxygen partial pressure (40 to 100mTorr) and substratetemperature. The crystallinity of the films also increased with the substrate temperature. The electrical resistivity measurementsshowed that the resistivity of the films decreased with an increase in Ta doping, which exhibited the lowest resistivity(ρ~1.1×10−3Ω·cm) for 10wt% Ta-doped SnO2 film, and then increased further. However, the resistivity continuouslydecreased with the oxygen partial pressure and substrate temperature. The optical bandgap of the 10wt% Ta-doped SnO2 filmincreased (3.67 to 3.78eV) with an increase in film thickness from 100-700nm, and the figure of merit revealed an increasingtrend with the film thickness.

ZnO thin films co-doped with Mg and Ga (MxGyZzO, x+y+z=1, x=0.05, y=0.02 and z=0.93) were preparedon glass substrates by RF magnetron sputtering with different sputtering powers ranging from 100W to 200W at a substratetemperature of 350oC. The effects of the sputtering power on the structural, morphological, electrical, and optical propertiesof MGZO thin films were investigated. The X-ray diffraction patterns showed that all the MGZO thin films were grown asa hexagonal wurtzite phase with the preferred orientation on the c-axis without secondary phases such as MgO, Ga2O3, orZnGa2O4. The intensity of the diffraction peak from the (0002) plane of the MGZO thin films was enhanced as the sputteringpower increased. The (0002) peak positions of the MGZO thin films was shifted toward, a high diffraction angle as thesputtering power increased. Cross-sectional field emission scanning electron microscopy images of the MGZO thin filmsshowed that all of these films had a columnar structure and their thickness increased with an increase in the sputtering power.MGZO thin film deposited at the sputtering power of 200W showed the best electrical characteristics in terms of the carrierconcentration (4.71×1020cm−3), charge carrier mobility (10.2cm2V−1s−1) and a minimum resistivity (1.3×10−3Ωcm). A UV-visible spectroscopy assessment showed that the MGZO thin films had high transmittance of more than 80% in the visibleregion and that the absorption edges of MGZO thin films were very sharp and shifted toward the higher wavelength side, from270nm to 340nm, with an increase in the sputtering power. The band-gap energy of MGZO thin films was widened from3.74eV to 3.92eV with the change in the sputtering power.

Changes in the surface morphology and light scattering of textured Al doped ZnO thin films on glasssubstrates prepared by rf magnetron sputtering were investigated. As-deposited ZnO:Al films show a hightransmittance of above 80% in the visible range and a low electrical resistivity of 4.5×10-4Ω·cm. The surfacemorphology of textured ZnO:Al films are closely dependent on the deposition parameters of heater temperature,working pressure, and etching time in the etching process. The optimized surface morphology with a cratershape is obtained at a heater temperature of 350oC, working pressure of 0.5 mtorr, and etching time of 45seconds. The optical properties of light transmittance, haze, and angular distribution function (ADF) aresignificantly affected by the resulting surface morphologies of textured films. The film surfaces, havinguniformly size-distributed craters, represent good light scattering properties of high haze and ADF values.Compared with commercial Asahi U (SnO2:F) substrates, the suitability of textured ZnO:Al films as frontelectrode material for amorphous silicon thin film solar cells is also estimated with respect to electrical andoptical properties.

첨가제로 Al2O3가 포함된 ZnO 소결체가 타깃을 이용하여 RF 마그네트론 스퍼터링법으로 Al이 첨가된 ZnO박막을 증착하고, 타깃에 첨가된 Al2O3</TEX>의 농도와 증착시 스퍼터링장치내의 기판위치에 따른 박막의 물성 변화를 고찰하였다. 타깃의 Al2O3 첨가농도가 2wt%인 경우에 비저항치 8 × 10-3 Ω-cm인 박막이 증차되었다. 또한 Al2O3</TEX>가 2wt%이상 첨가된 경우는 모든 Al이 박막내부에서 Zn를 치환하여 전자주게로의 역할을 하지 못하고, 오히려 치환되지 못한 Al원자의 중성 불순물 산란효과에 의해 박막의 비저항이 증가하였다. 타깃의 마모영역 위에서 증착된 Al을 첨가한 ZnO 박막은 그 영역 KR에서 증착된 박막보다 높은 비저항값을 나타냈으며, 이는 큰 에너지를 가지는 산소입자의 충돌에 기인한 것으로 여겨진다.