Scanning probe microscopy (SPM) has become an indispensable tool in efforts to develop the next generation of nanoelectronic devices, given its achievable nanometer spatial resolution and highly versatile ability to measure a variety of properties. Recently a new scanning probe microscope was developed to overcome the tip degradation problem of the classic SPM. The main advantage of this new method, called Reverse tip sample (RTS) SPM, is that a single tip can be replaced by a chip containing hundreds to thousands of tips. Generally for use in RTS SPM, pyramid-shaped diamond tips are made by molding on a silicon substrate. Combining RTS SPM with Scanning spreading resistance microscopy (SSRM) using the diamond tip offers the potential to perform 3D profiling of semiconductor materials. However, damage frequently occurs to the completed tips because of the complex manufacturing process. In this work, we design, fabricate, and evaluate an RTS tip chip prototype to simplify the complex manufacturing process, prevent tip damage, and shorten manufacturing time.

The Cu2ZnSn(SxSe1-x)4 (CZTSSe) absorbers are promising thin film solar cells (TFSCs) materials, to replace existing Cu(In,Ga)Se2 (CIGS) and CdTe photovoltaic technology. However, the best reported efficiency for a CZTSSe device, of 13.6 %, is still too low for commercial use. Recently, partially replacing the Zn2+ element with a Cd2+element has attracting attention as one of the promising strategies for improving the photovoltaic characteristics of the CZTSSe TFSCs. Cd2+ elements are known to improve the grain size of the CZTSSe absorber thin films and improve optoelectronic properties by suppressing potential defects, causing short-circuit current (Jsc) loss. In this study, the structural, compositional, and morphological characteristics of CZTSSe and CZCTSSe thin films were investigated using X-ray diffraction (XRD), X-ray fluorescence spectrometer (XRF), and Field-emission scanning electron microscopy (FE-SEM), respectively. The FE-SEM images revealed that the grain size improved with increasing Cd2+ alloying in the CZTSSe thin films. Moreover, there was a slight decrease in small grain distribution as well as voids near the CZTSSe/Mo interface after Cd2+ alloying. The solar cells prepared using the most promising CZTSSe absorber thin films with Cd2+ alloying (8 min. 30 sec.) exhibited a power conversion efficiency (PCE) of 9.33 %, Jsc of 34.0 mA/cm2, and fill factor (FF) of 62.7 %, respectively.

Cu2ZnSn(S,Se)4 (CZTSSe) based thin-film solar cells have attracted growing attention because of their earthabundant and non-toxic elements. However, because of their large open-circuit voltage (Voc)-deficit, CZTSSe solar cells exhibit poor device performance compared to well-established Cu(In,Ga)(S,Se)2 (CIGS) and CdTe based solar cells. One of the main causes of this large Voc-deficit is poor absorber properties for example, high band tailing properties, defects, secondary phases, carrier recombination, etc. In particular, the fabrication of absorbers using physical methods results in poor surface morphology, such as pin-holes and voids. To overcome this problem and form large and homogeneous CZTSSe grains, CZTSSe based absorber layers are prepared by a sputtering technique with different RTA conditions. The temperature is varied from 510 oC to 540 oC during the rapid thermal annealing (RTA) process. Further, CZTSSe thin films are examined with X-ray diffraction, X-ray fluorescence, Raman spectroscopy, IPCE, Energy dispersive spectroscopy and Scanning electron microscopy techniques. The present work shows that Cu-based secondary phase formation can be suppressed in the CZTSSe absorber layer at an optimum RTA condition.

Zinc oxide (ZnO) based transparent conducting oxides (TCO) thin films, are used in many applications such as solar cells, flat panel displays, and LEDs due to their wide bandgap nature and excellent electrical properties. In the present work, fluorine and aluminium-doped ZnO targets are prepared and thin films are deposited on soda-lime glass substrate using a RF magnetron sputtering unit. The aluminium concentration is fixed at 2 wt%, and the fluorine concentration is adjusted between 0 to 2.0 wt% with five different concentrations, namely, Al2ZnO98(AZO), F0.5AZO97.5(FAZO1), F1AZO97(FAZO2), F1.5AZO96.5(FAZO3), and F2AZO96(FAZO4). Thin films are deposited with an RF power of 40 W and working pressure of 5 m Torr at 270 oC. The morphological analysis performed for the thin film reveals that surface roughness decreases in FAZO1 and FAZO2 samples when doped with a small amount of fluorine. Further, optical and electrical properties measured for FAZO1 sample show average optical transmissions of over 89 % in the visible region and 82.5 % in the infrared region, followed by low resistivity and sheet resistance of 3.59 × 10−4 Ωcm and 5.52 Ω/sq, respectively. In future, these thin films with excellent optoelectronic properties can be used for thin-film solar cell and other optoelectronics applications.

Recent advances in technology using ultra-thin noble metal film in oxide/metal/oxide structures have attracted attention because this material is a promising alternative to meet the needs of transparent conduction electrodes (TCE). AZO/ Ag/AZO multilayer films are prepared by magnetron sputtering for Cu2ZnSn(S,Se)4 (CZTSSe) of kesterite solar cells. It is shown that the electrical and optical properties of the AZO/Ag/AZO multilayer films can be improved by the very low resistivity and surface plasmon effects due to the deposition of different thicknesses of Ag layer between oxide layers fixed at AZO 30 nm. The AZO/Ag/AZO multilayer films of Ag 15 nm show high mobility of 26.4 cm2/Vs and low resistivity and sheet resistance of 3.58*10−5 Ωcm and 5.0 Ω/sq. Also, the AZO/Ag (15 nm)/AZO multilayer film shows relatively high transmittance of more than 65% in the visible region. Through this, we fabricated CZTSSe thin film solar cells with 7.51% efficiency by improving the short-circuit current density and fill factor to 27.7 mV/cm2 and 62 %, respectively.

Cu2ZnSn(S,Se)4(CZTSSe) thin film solar cells areone of the most promising candidates for photovoltaic devices due to their earth-abundant composition, high absorption coefficient and appropriate band gap. The sputtering process is the main challenge to achieving high efficiency of CZTSSe solar cells for industrialization. In this study, we fabricated CZTSSe absorbers on Mo coated soda lime glass using different pressures during the annealing process. As an environmental strategy, the annealing process is performed with S and Se powder, without any toxic H2Se and/or H2S gases. Because CZTSSe thin films have a very narrow stable phase region, it is important to control the condition of the annealing process to achieve high efficiency of the solar cell. To identify the effect of process pressure during the sulfo-selenization, we experiment with varying initial pressure from 600 Torr to 800 Torr. We fabricate a CZTSSe thin film solar cell with 8.24 % efficiency, with 435 mV for open circuit voltage(VOC) and 36.98 mA/cm2 for short circuit current density(JSC), under a highest process pressure of 800 Torr.

담관의 게실은 Todani 분류에 부합하지 않는 드문 형태의 담관의 낭성 확장이며, 질환의 희소성으로 인하여 진료 현장에서 진단이나 치료에 어려움을 겪을 수 있다. 본 증례보고에서는 복통을 주소로 내원한 57세 여성 환자에서 발생한 간외 좌측 담관 게실의 증례를 문헌고찰과 함께 보고하고자 한다. 내원 당시 환자는 간기능 검사에서의 경미한 증가 외에 혈액검사상 이상 소견은 보이지 않았다. 전산화단층촬영과 자기공명 담도췌관조영술에서 간내담관의 합류 부분 근처에 슬러지 볼을 포함한 낭성 병변이 보였으나 병변의 기원은 명확히 보이지 않았다. 임상적으로는 Todani II형 총담관낭이 의심되었다. 환자의 복통이 지속되어 해당 병변에 대하여 수술적 절제를 시행하였고 수술 결과 좌측 담관 게실로 진단되었다. 절제된 조직은 병리학적 검사상 담도 상피로 덮인 게실로 확인되었다. 수술 후 합병증은 발생하지 않았으며 수술적 제거 후 환자의 증상은 호전되었다.

Cu2ZnSn(S,Se)4 (CZTSSe) films were prepared on Mo coated soda lime glass substrates by sulfo-selenization of sputtered stacked Zn-Sn-Cu(CZT) precursor films. The precursor was dried in a capped state with aqueous NaOH solution. The CZT precursor films were sulfo-selenized in the S + Se vapor atmosphere. Sodium was doped during the sulfo-selenization treatment. The effect of sodium doping on the structural and electrical properties of the CZTSSe thin films were studied using FE-SEM(field-emission scanning electron microscopy), XRD(X-ray diffraction), XRF(X-ray fluorescence spectroscopy), dark current, SIMS(secondary ion mass spectrometry), conversion efficiency. The XRD, XRF, FE-SEM, Dark current, SIMS and cell efficiency results indicated that the properties of sulfo-selenized CZTSSe thin films were strongly related to the sodium doping. Further detailed analysis and discussion for effect of sodium doping on the properties CZTSSe thin films will be discussed.

미리찌 증후군은 담낭결석증의 드문 합병증으로, 담낭 경부나 담낭관의 결석에 의한 압박으로 인해 총간관의 폐쇄가 발생하게 된다. 미리찌 증후군은 수술적 치료를 하게 되며 그 방법은 질환의 세부 분류에 따라 다양하다. 미리찌 증후군의 외과적 치료 후 발생한 담관 협착은 드문 합병증이며 담도-장 문합술을 시행한 환자에서 이를 내시경적으로 치료하는 것은 불가능하다. 본 증례는 미리찌 증후군의 수술적 치료 후 발생한 담관 문합부 협착을 장기간 경피경간 담도배액술로 치료하여 이를 문헌고찰과 함께 보고하는 바이다.

고압균질화 기반 nanosuspension화은 난용 혹은 불용인 기능성 물질의 가용성을 높이는 기술로서 식품산업체로부터 관심을 받고 있다. 그러나 nanosuspension은 나노 크기로 분산된 난용성 입자들은 응집 또는 Ostwald ripening 현상에 쉽게 노출되기 때문에, 저장안정성이 낮다. 그러므로 이러한 nanosuspension에 유화제 및 고분자 물질 등의 분산안정제를 도입함으로써 위의 현상을 지연시키거나 방지하기 위해 반드시 필요하다. 이 연구는 분산안정제의 특성이 nanosuspension화된 분지쇄아미노산의 용해도 및 저장안정성에 미치는 영향을 평가했다. Tween 80, Span 80 또는 lysolecithin을 10 mM 인산 완충 용액(pH 7)에 녹이고, pH를 3 또는 6으로 보정하여 안정제 용액을 제조하였다. 분지쇄아미노산 혼합물(L-leucine:L-isoleucine:L-valine=2:1:1)을 최종 농도가 5%(w/v)가 되도록 안정제 용액에 첨가 하였다. 모든 분지쇄아미노산 현탁액을 25°C에서 2 시간 동안 교반하였다. 분지쇄아미노산를 함유한 나노서스펜션을 제조하기 위해서 70°C로 예열된 분지쇄아미노산 현탁액을 고압균질화기를 사용하여 100 MPa에서 5 회 균질화를 진행하였다. pH에 관계없이 고압균질화를 통해 분지쇄아미노산의 가용성을 증가되었지만, 가용성이 장기간 동안 유지 되지 않았다. 분산안정제에 의해 분지쇄아미노산의 포화 농도는 증가하였고, 분지쇄아미노산의 포화 농도 증가에 대한 안정제의 영향은 pH 6에서 더 확연했다. pH 6에서 Tween 80은 분지쇄아미노산와의 혼합 비율과는 무관하게 분지쇄아미노산 nanosuspension의 저장안정성을 크게 증가 시켰지만, pH 3에서는 그렇지 않았다. 그러나 lysolecithin과 Span 80을 적용한 분지쇄아미노산 nanosuspension의 저장안정성은 pH와 안정제의 혼합 비율에 따라 영향을 받았다.

국가 지형도에 있어 도엽명은 도엽의 효율적인 관리 및 검색을 위한 인덱스이면서 동시에 특정 도엽의 위치를 참조할 수 있게 하는 지리참조 체계의 역할을 수행한다. 우리나라의 지형도 제작 역사가 100여 년이 지나고 있으나 도엽명에 대한 체계적인 연구는 거의 전무하다. 본 연구의 주된 목적은 국가 지형도의 도엽명 부여 원칙을 정립하고, 이를 실제 적용하여 현행 도엽명의 적절성을 검토하는 것이다. 본 연구의 주요 결과는 다음과 같다. 첫째, 국가 지형도 도엽명 부여 원칙의 필요성을 살펴본 후 도엽명 부여 원칙을 수립하기 위한 실행 방안을 제시하였다. 둘째, 현행 지형도 도엽명을 기초로 행정구역명 중심의 도엽명 부여 원칙을 제안하였다. 셋째, 이 원칙에 입각하여 현행 1:50,000 지형도 도엽명을 검토하였다. 그 결과 제안된 원칙을 적용할 경우 현행 도엽명 가운데 약 20% 정도가 변경 가능한 도엽으로 나타났다. 본 연구에서 제안된 원칙은 향후 발생 가능한 도엽명의 신규 부여 및 갱신 과정에 효과적으로 적용될 수 있을 것으로 기대된다.

Cu2ZnSn(Sx,Se1-x)4 (CZTSSe) thin films were prepared by sulfurization of evaporated precursor thin films. Precursor was prepared using evaporation method at room temperature. The sulfurization was carried out in a graphite box with S powder at different temperatures. The temperatures were varied in a four step process from 520˚C to 580˚C. The effects of the sulfurization temperature on the micro-structural, morphological, and compositional properties of the CZTSSe thin films were investigated using X-ray diffraction (XRD), Raman spectra, field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The XRD and Raman results showed that the sulfurized thin films had a single kesterite crystal CZTSSe. From the FE-SEM and TEM results, the Mo(Sx,Se1-x)2 (MoSSe) interfacial layers of the sulfurized CZTS thin films were observed and their thickness was seen to increase with increasing sulfurization temperature. The microstructures of the CZTSSe thin films were strongly related to the sulfurization temperatures. The voids in the CZTSSe thin films increased with the increasing sulfurization temperature.

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.

Chalcogenide-based semiconductors, such as CuInSe2, CuGaSe2, Cu(In,Ga)Se2 (CIGS), and CdTe have attracted considerable interest as efficient materials in thin film solar cells (TFSCs). Currently, CIGS and CdTe TFSCs have demonstrated the highest power conversion efficiency (PCE) of over 11% in module production. However, commercialized CIGS and CdTe TFSCs have some limitations due to the scarcity of In, Ga, and Te and the environmental issues associated with Cd and Se. Recently, kesterite CZTS, which is one of the In- and Ga- free absorber materials, has been attracted considerable attention as a new candidate for use as an absorber material in thin film solar cells. The CZTS-based absorber material has outstanding characteristics such as band gap energy of 1.0 eV to 1.5 eV, high absorption coefficient on the order of 104cm-1, and high theoretical conversion efficiency of 32.2% in thin film solar cells. Despite these promising characteristics, research into CZTS-based thin film solar cells is still incomprehensive and related reports are quite few compared to those for CIGS thin film solar cells, which show high efficiency of over 20%. The recent development of kesterite-based CZTS thin film solar cells is summarized in this work. The new challenges for enhanced performance in CZTS thin films are examined and prospective issues are addressed as well.