Effects of Cu/In Compositional Ratio on the Characteristics of CuInS2 Absorber Layers Prepared by Sulfurization of Metallic Precursors

Seung Hwan Lee,신승욱,Jun Hee Han,이정용,Myeong Gil Kang,G. L. Agawane,Jae Ho Yun,Jong Ha Moon,Jin Hyeok Kim 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.2

This paper investigates the effects of the Cu/In compositional ratio on morphological, structural and optical properties of CuInS2 (CIS) absorber layers formed by sulfurization of In/Cu stacked precursors. In/Cu stacked precursors were prepared on Mo-coated soda-lime glass substrates by DC magnetron sputtering method. The Cu/In compositional ratio in the precursor thin film was varied from 0.55 to 1.44. The as-deposited stacked precursor thin films were sulfurized using a tubular furnace annealing system in a mixture of N2 (95%) +H2S (5%) atmosphere at 450°C for 1 hour. X-ray diffraction patterns and Raman spectra results showed that the sulfurized thin films contained both tetragonal CIS and a Cu-based secondary phase, except for the film with a Cu/In compositional ratio of 0.55. Field emission-scanning electron microscopy study showed that the microstructure of the sulfurized CIS thin films became denser with increasing Cu/In compositional ratio. Optical properties of the CIS thin films showed that all the CIS thin films had a good absorption coefficient over 104cm−1in the visible region. The direct band gap energy of the sulfurized CIS thin films decreased from 1.39 eV to 1.08 eV with increasing Cu/In compositional ratio. These results demonstrated the effect of the Cu/In compositional ratio on the properties of the CIS thin films and the consequent importance of precisely controlling the metal ratio in the precursor film in order to control the properties of absorber layers in thin film solar cells.

13C 및 15N 안정성 동위원소 비율 분석에 의한 원료의약품에서 에페드린 및 슈도에페드린의 기원 판별

백승경(SeungKyung Baeck),Tetsuo Nagano,최화경(HwaKyung Choi),정희선(HeeSun Chung),표명윤(MyungYun Pyo),정진일(JinIl Jeong),양원경(Wonkyang Yang),Yukiko Makino,장문희(MoonHee Jang) 대한약학회 2009 약학회지 Vol.53 No.5

The abuse of methamphetamine (MA) is one of the most serious drug abuses in Asia. And, the prevention of precursor production for abuse drug is one of the most effective drug control system. Isotope ratio analysis at natural abundance levels have been used to establish the environmental source or the geographic origin of various biological and nonbiological materials. Ephedrine, the precursor of MA, is produced by one of three methods; extraction from Ephedra plants, full chemical synthesis or via a semi-synthetic process involving the fermentation of sugar, followed by amination. We investigated the origin of ephedrine and pseudoephedrine based on the carbon and nitrogen values for nineteen pharmaceutical powder materials (PPMs) obtained from pharmaceutical company in Korea by stable isotope ratio mass spectrometry coupled to an elemental analyser (EA-IRMS). The carbon delta values for the ephedrine and pseudoephedrine were -24.21~-22.72 (mean=-23.72) ‰ and -23.79~-22.71 (mean=-23.48) ‰. The nitrogen delta values were 3.51~5.55 (4.43) ‰ and 2.24~8.22 (5.42) ‰. These results indicate that PPMs are semi-synthetic products. Therefore the origins of ephedrine (natural, semi-synthetic or synthetic) could be discriminated by using carbon and nitrogen stable isotope ratios. we are sure tat this stable isotope ratio analysis can discriminate the origins of precursors of methamphetamine.

수열법으로 성장한 ZnO Nanorod/ZnO/Si(100)의 특성

정민호,진용식,최성민,한덕동,최대규,Jeong, Min-Ho,Jin, Yong-Sik,Choi, Sung-Min,Han, Duk-Dong,Choi, Dae-Kue 한국재료학회 2012 한국재료학회지 Vol.22 No.4

Nanostructures of ZnO, such as nanowires, nanorods, nanorings, and nanobelts have been actively studied and applied in electronic or optical devices owing to the increased surface to volume ratio and quantum confinement that they provide. ZnO seed layer (about 40 nm thick) was deposited on Si(100) substrate by RF magnetron sputtering with power of 60 W for 5 min. ZnO nanorods were grown on ZnO seed layer/Si(100) substrate at $95^{\circ}C$ for 5 hr by hydrothermal method with concentrations of $Zn(NO_3)_2{\cdot}6H_2O$ [ZNH] and $(CH_2)_6N_4$ [HMT] precursors ranging from 0.02M to 0.1M. We observed the microstructure, crystal structure, and photoluminescence of the nanorods. The ZnO nanorods grew with hexahedron shape to the c-axis at (002), and increased their diameter and length with the increase of precursor concentration. In 0.06 M and 0.08 M precursors, the mean aspect ratio values of ZnO nanorods were 6.8 and 6.5; also, ZnO nanorods had good crystal quality. Near band edge emission (NBE) and a deep level emission (DLE) were observed in all ZnO nanorod samples. The highest peak of NBE and the lower DLE appeared in 0.06 M precursor; however, the highest peak of DLE and the lower peak of NBE appeared in the 0.02 M precursor. It is possible to explain these phenomena as results of the better crystal quality and homogeneous shape of the nanorods in the precursor solution of 0.06 M, and as resulting from the bed crystal quality and the formation of Zn vacancies in the nanorods due to the lack of $Zn^{++}$ in the 0.02 M precursor.

Effects of diff erent NO 3 − :NH 4 + ratios on the photosynthesis and ultrastructure of lettuce seedlings

Xu Zhu,Rui Yang,Yingyan Han,Jinghong Hao,Chaojie Liu,Shuangxi Fan 한국원예학회 2020 Horticulture, Environment, and Biotechnology Vol.61 No.3

Nitrate nitrogen (NO 3− ) and ammonium N (NH 4+ ) are the two main forms of nitrogen (N). The eff ects of the NO 3− :NH 4+ ratio(0:100, 25:75, 50:50, 75:25, and 100:0) in the nutrient solution on growth, pigment content, photosynthetic parameters, chlorophyll(Chl) precursor content, and chloroplast mitochondrial ultrastructure of lettuce leaves were evaluated to determine theappropriate N ratio for the growth of lettuce. The results showed that a ratio of nitrate to ammonium of 75:25 compared withthe single N form resulted in signifi cantly higher fresh weights in the shoots and the lower parts of the lettuce. The growthrate, as indicated by the CO 2 response curve, was increased because of the carboxylation effi ciency and dark respiration rate(Rday) of the lettuce seedlings, and the diff erence between the light compensation point and CO 2 compensation point wasreduced under single nitrate N treatment. The contents of δ-aminolevulinic acid (ALA), porphobilinogen, uroporphyrinogenIII, protoporphyrin IX, and Mg-protoporphyrin IX in seedlings at 75:25 nitrate:ammonium were higher than those inseedlings under the other treatments. The contents of Chl a and b were also the highest when the ratio of nitrate ammoniumwas 75:25. The chloroplast structure of lettuce leaves was intact, the cell membrane was completely closed to the cell wall,and the organelles were closely arranged on the cell membrane. The chloroplast was spindle-shaped and full of vesicles. The whole mitochondria were rich, the base particles were rich, the base granules were clear and rich, and the mitochondriaexhibited the overall best state with a complete structure, rich sputum, and dense inclusions. The above results show that thenutrient solution with a ratio of nitrate to ammonium of 75:25 was more conducive to Chl synthesis and the promotion ofphotosynthesis and root growth in lettuce seedlings than the other treatments. The single nitrate N nutrient solution reducedChl synthesis and photosynthesis in lettuce seedlings, while the single ammonium N nutrient solution aff ected the growthof lettuce seedlings, resulting in lower growth of lettuce shoots and roots. Therefore, the nutrient solution ratio of nitrate toammonium of 75:25 is the most suitable for the lettuce seedling growth.

Impacts of Sr2+ and Annealing Temperature on the Composition, Structure, and Magnetic Properties of SrFe12O19 Synthesized by Tartrate Precursor Route

M. M. Hessien,Mahdi Albogamy,Mohammed Alsawat,Abdulrahman Alhadhrami 한국자기학회 2023 Journal of Magnetics Vol.28 No.2

Hexagonal M-type strontium ferrite (SrFe12O19) has been fabricated through a simple self-combustion tartrate precursor approach to producing a homogenous powder with a homogeneous shape and limited size distribution at low-processing temperatures. The impacts of the Sr2+:Fe3+ molar ratio and the annealing temperature on formation, morphological structure, crystallite size, and magnetic performance were studied. The powders were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) profile, and vibrating sample magnetometer (VSM). The development of crystalline single-phase Sr-hexagonal ferrite occurred at ≥ 1100 °C and Sr2+:Fe3+ molar ratios 1.1:12-1.3:12. Existence of α-Fe2O3 and impurities in the hexagonal powders increases the lattice parameters while higher annealing temperature decreases it. The c/a ratios of as-prepared samples (~3.911-3.920) are comfortably within the range of ratios for M-type structures. The platelet-like structure has appeared at an annealing temperature ≥ 1000 °C. The wide saturation magnetization (37.26-66.19 emu/g) and coercivity (275.09-2107.8Oe) were accomplished at diverse synthesis conditions and reached the greatest values at 1350 °C. The squareness ratios (Mr/Ms) for all studied samples are <0.5, which is for multimagnetic domains.

Efficient hydrogen generation using morphology-controlled Sb₂Se₃ photocathode

Jaemin Park,Wooseok Yang,Yunjung Oh,Jeiwan Tan,Hyungsoo Lee,Jooho Moon 한국진공학회 2019 한국진공학회 학술발표회초록집 Vol.2019 No.2

Controlled morphology of Sb₂Se₃ photocathodes for water splitting through facile changing ratio of Se/Sb

박재민,양우석,오윤정,탄제완,이형수 한국진공학회 2017 한국진공학회 학술발표회초록집 Vol.2017 No.8