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ABSTRACT: Non-crystalline copper indium disulphide (CuInS2) thin films had been deposited on ITO glass by chemical bath deposition (CBD) in acid conditions. Then polycrystalline CuInS2 films were obtained after sulfuration in sulfur atmosphere at 450°C for 1.5h. The films had been characterized by X-ray
diffraction (XRD), scanning electronic microscopy (SEM), Raman scattering measurements and energy dispersive X-ray analysis
(EDX). The optical and electrical property of the thin films was also measured. The results showed that the pure, flatness,
and well crystallized CuInS2 thin films with good electrical and optical property had been obtained, meaning that the chemical bath deposition in acid
conditions is suitable for the deposition of CuInS2 thin films.
Journal of Materials Science Materials in Electronics 05/2012; 20(7):609-613. · 1.08 Impact Factor
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ABSTRACT: This work focuses on the synthesis of tetragonal zirconia (ZrO2) nanocrystallites with diameters of 5 nm by a simple hydrothermal process in the presence of hydrazine hydrate. Structural characterization of the ZrO2 products using X-ray diffraction and Raman spectroscopy revealed that the predominant crystal phase was the tetragonal phase. High-resolution transmission electron microscopy images further showed that that the diameter of the majority of the tetragonal ZrO2 nanocrystallites was <5 nm. Furthermore, we discussed the mechanism of the hydrothermal process and the critical roles of hydrazine hydrate in the hydrothermal formation of the small-sized ZrO2 nanocrystallites.
Journal of the American Ceramic Society 03/2007; 90(4):1334 - 1338. · 2.27 Impact Factor
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ABSTRACT: The behavior of the copper precipitation in the large-diameter Czochralski silicon (Cz–Si) annealed at 1100 °C followed by air cooling or slow cooling was studied by means of scanning infrared microscopy (SIRM), optical microscopy, and surface photovoltage. For the air-cooled specimen, a high density of copper-precipitate colonies with strong contrast could be easily found in the A-defect zone, while in the D-defect zone of the same specimen almost no colonies could be observed through SIRM. However, optical images showed that the higher density of the etching pits induced by the copper-precipitate colonies occurred in the D-defect zone, which indicates that the copper-precipitate colonies in the D-defect zone was below the detection limitation of SIRM. This suggestion was confirmed by minority-carrier diffusion-length mapping, which revealed that the diffusion length of the minority carriers in the D-defect zone was noticeably lower than that in the A-defect zone. As for the slow-cooled specimen, big star-like colonies formed both in the D-defect zone and A-defect zone, but the diffusion length of the minority carriers in the D-defect zone was also lower than that in the A-defect zone. On the basis of experiments, it is suggested that the as-grown vacancies or their related defects in the D-defect zone enhance the nucleation of copper precipitation either under air cooling or under slow cooling, resulting in the lower diffusion length of minority carriers.
Journal of Applied Physics 04/2005; 97(9):094909-094909-4. · 2.17 Impact Factor
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ABSTRACT: The impact of the boundary plane and impurity contamination on the recombination activity of Σ3 boundaries in multicrystalline silicon (mc-Si) was studied by means of electron-beam-induced current (EBIC) technique. In the as-grown contamination-free mc-Si, the EBIC contrast of different Σ3 boundaries was in the order of Σ3{111}<Σ3{110}<Σ3{112}. This order may be attributed to the difference in the defect density of the Σ3 boundaries due to the effect of the boundary plane. But the maximum EBIC contrast did not exceed 2% at 300 K, suggesting that the Σ3 boundaries are originally electrically inactive and the boundary plane has no significant effect on their recombination activity. When contaminated with Fe at 900 °C, the EBIC contrasts of the Σ3{110} and Σ3{112} increased at 300 K, whereas that of the Σ3{111} was still weak (<3%). This variation in the EBIC contrast may be related to the effect of boron and it is also indicated that the Σ3{111} has the weakest gettering ability. When contaminated with Fe at 1100 °C, the EBIC contrasts of all the Σ3 boundaries continued to increase and bright-denuded zones developed around the boundaries. The Σ3 boundaries in the 1100 °C air-cooled mc-Si showed stronger EBIC contrasts and broader denuded zones than those in the 1100 °C quenched one. This phenomenon was explained in terms of the precipitation of Fe. The precipitation of Fe at grain boundaries (GBs) was affected by both the GB type and cooling rate, that is, Fe is easier to form precipitates onto the Σ3{110} and Σ3{112} boundaries during slow cooling.
Journal of Applied Physics 12/2004; 97(3):033701-033701-5. · 2.17 Impact Factor
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ABSTRACT: The texturization of cast multicrystalline silicon (mc-Si) for solar cells with alkaline or acidic solution has been investigated, and two theoretical models were built on the basis of surface morphologies. For alkaline etching, tilted pyramid structure could be formed on the surface. It is reported that when the tilted angle, which is the angle between (100)-plane and as-cut surface, is larger than the critical angle (20°), the reflectance rapidly increases with the deviation from 100 orientation. For acidic etching, spherical structure was generated. If the ratio, which is the ratio of depth (h) and radius (r) of the spherical structure, is less than the critical value (0.29), the second reflection cannot take place. Therefore, improving the ratio of i and r is one effective way to decrease the reflectance of cast mc-Si, which was proved by subsequent experiment. With the addition of sodium nitrite (NaNO2) or sodium phosphate tribasic (Na3PO4 12H2O) into the acid etchant, it was found that the reflectance decreased remarkably. Finally the formation mechanism of spherical pits in acid etched mc-Si was discussed.
Semiconductor Science and Technology 01/2004; 19(3):485. · 1.72 Impact Factor
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ABSTRACT: The influence of copper precipitation on oxygen precipitation in Czochralski-grown silicon was investigated by Fourier transform infrared spectroscopy, defect etching and transmission electron microscopy combined with energy dispersive x-ray analysis. It was found that interstitial copper almost had no influence on oxygen precipitation but copper precipitation remarkably enhanced oxygen precipitation. Furthermore, the enhancement of copper precipitation under air cooling (30 K s−1) on oxygen precipitation subsequently was much more noticeable than that of copper precipitation under slow cooling (0.3 K s−1). It was also observed that the dislocations induced by oxygen precipitates occurred in the samples without copper contamination, but in the samples experiencing copper precipitation, oxygen preferably precipitated on the dislocations induced by copper precipitates, or dislocation-free oxygen precipitates occurred. These results indicate that heterogeneous nucleation of oxygen precipitates on dislocations and successful release of the stress from oxygen precipitation are responsible for the enhancement of oxygen precipitation.
Semiconductor Science and Technology 11/2003; 19(3):299. · 1.72 Impact Factor
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ABSTRACT: Effect of intrinsic point defects on copper precipitation in large-diameter Czochralski silicon annealed at 1100 °C under air cooling was studied by means of scanning infrared microscopy (SIRM), optical microscopy (OM), and transmission electron microscopy (TEM). The SIRM images showed that, in the A-defect zone of the Cu-contaminated silicon wafers, the copper-precipitate colonies with larger size were observed, while in the D-defect zone almost no copper precipitates could be observed. However, the OM results revealed that the density of etching pits in the D-defect zone was higher than that in the A-defect zone, indicating that the copper precipitates with smaller size and higher density formed in the D-defect zone. The TEM investigation showed that the size of copper precipitate colonies in the A-defect zone was about 300 nm, while that in the D-defect zone was about 50 nm. It is considered that as-grown vacancies in the D-defect zone enhanced the nucleation of copper precipitates but hindered their growth, whereas the role of as-grown interstitial silicon on copper precipitation was inverse. © 2003 American Institute of Physics.
Applied Physics Letters 10/2003; 83(15):3048-3050. · 3.84 Impact Factor
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ABSTRACT: A model, including segregation from silicon melt to silicon crystal as well as evaporation from silicon melt to Ar atmosphere, was established for simulating the oxygen distribution in multicrystalline silicon (mc-si) ingot, which shows good agreement with the experimental results. According to this model, the oxygen distribution in the bottom of ingot is mainly determined by the evaporation of oxygen, whereas that in the top of ingot is dominated by the segregation of oxygen. Furthermore, it could be found that the Oi profiles in growth direction of ingots become more and more steeper with the increase of the exponent X.
Solar Energy Materials and Solar Cells 91(18):1688-1691. · 4.54 Impact Factor
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ABSTRACT: The behavior of copper precipitation in cast multicrystalline silicon (mc-Si) annealed at different temperatures under air cooling (30 K/s) or slow cooling (0.3 K/s) was investigated by scanning infrared microscopy (SIRM). Comparing to Czochralski-grown silicon (Cz-Si), copper precipitated more easily in mc-Si, and the lowest temperature of copper precipitation in mc-Si was about 700 °C, lower than that in Cz-Si. It was also observed that copper preferably precipitated on grain boundaries so that near the grain boundaries the denuded zone formed. The results indicate that the defects including dislocations, grain boundaries and microdefects, as the heteronucleation sites, enhanced copper precipitation. Moreover, cooling rates had a great influence on the copper precipitation, especially at lower annealing temperatures. Generally air cooling led to the formation of high density of copper-precipitate colonies.
Infrared Physics & Technology.
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ABSTRACT: The iron precipitation in as-received Czochralski (CZ) silicon during low temperature from 300 to 700 °C was investigated. It was found that the iron precipitation rate was increased in turn from 300 to 700 °C. It was also found that the iron could form small precipitates even at low concentration. Moreover, iron precipitation was revealed as the diffusion-limited process, which could be described properly by Ham's law. This performance of iron precipitation in as-received CZ silicon was considered to be significantly influenced by the grown-in oxygen precipitates because of the fact that the grown-in oxygen precipitates could act as the heterogeneous nuclei for interstitial iron.
Materials Science in Semiconductor Processing.
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ABSTRACT: In comparison with small-diameter (4 in), nickel precipitation in large-diameter (8 in) Czochralski silicon (Cz–Si) under air-cooling or slow-cooling was investigated by scanning infrared microscopy (SIRM) and optical microscopy. It was found that a nickel precipitate-free zone with a thickness of 250 μm near the surface formed in the specimen of small-diameter Cz–Si annealed at 1100°C under air-cooling, while no nickel precipitates could be observed under slow-cooling. However, nickel precipitates could be found in all the specimens of large-diameter Cz–Si annealed at 1100°C despite different cooling rates. These results indicate that nickel precipitation depends not only on the cooling rate but also intrinsic defects or their complexes in Cz–Si. Finally, the mechanism of nickel precipitation in larger-diameter Cz–Si is discussed.
Physica B: Condensed Matter.
