• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.589-589
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• 2012

Indium sulfide thin films have been grown onto glass substrates using radio frequency magnetron sputtering at room temperature. The as-deposited film were annealed in nitrogen atmosphere at different temperatures of 100, 200, 300, 400 and $500^{\circ}C$ with an 1 h annealing time. The effect of annealing temperature on composition, structure, morphology and optical properties of the as-grown In2S3 films has been studied. The XRD results indicate that the as-deposited films are composed by a mixture of both cubic ${\alpha}$ and ${\beta}$ crystalline phases, with some fraction of tetragonal phase. The thermal annealing on the films produces the conversion of the cubic crystalline phases to the tetragonal ${\beta}$ one and a crystalline reorientation of the latter phase. The surface morphological analysis reveals that the films grown at $300^{\circ}C$ have an average grain size of ~ 58 nm. These films show a S/In ratio of 0.99. The optical band gap is found to be direct and the films grown at $300^{\circ}C$ shows a higher optical transmittance of 80% and an energy band gap of 2.52 eV.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.179.1-179.1
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• 2015

Thickness-dependent electrical, structural, and optical properties of zinc oxide (ZnO) thin films on polyethylene terephthalate (PET) substrates were investigated in the very thin thickness range of 20 to 120 nm. A very unusual transition phenomenon, in which electrical resistance increases with an increase in film thickness, was observed. From structural and compositional analyses, this transition behavior was explained to arise from metallic Zn agglomerates dispersed in non-crystalline Zn-O matrix. It was unveiled that film thickness more than 80 nm is required for the development of hexagonal crystal structure of ZnO. ZnO films on PET substrates exhibited high optical transmittance and good mechanical flexibility in the thickness range. The results of this study would provide a valuable guideline for the design of ZnO thin films on organic substrates for practical applications.

• Korean Journal of Materials Research
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• v.15 no.10
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• pp.626-631
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• 2005

GaN-related compound semiconductors were grown on the corrugated interface substrate using a metalorganic chemical vapor deposition system to increase the optical power of white LEDs. The patterning of substrate for enhancing the extraction efficiency was processed using an inductively coupled plasma reactive ion etching system and the surface morphology of the etched sapphire wafer and that of the non-etched surface were investigated using an atomic force microscope. The structural and optical properties of GaN grown on the corrugated interface substrate were characterized by a high-resolution x-ray diffraction, transmission electron microscopy, atomic force microscope and photoluminescence. The roughness of the etched sapphire wafer was higher than that of the non-etched one. The surface of III-nitride films grown on the hemispherically patterned wafer showed the nano-sized pin-holes that were not grown partially. In this case, the leakage current of the LED chip at the reverse bias was abruptly increased. The reason is that the hemispherically patterned region doesn't have (0001) plane that is favor for GaN growth. The lateral growth of the GaN layer grown on (0001) plane located in between the patterns was enhanced by raising the growth temperature ana lowering the reactor pressure resulting in the smooth surface over the patterned region. The crystal quality of GaN on the patterned substrate was also similar with that of GaN on the conventional substrate and no defect was detected in the interface. The optical power of the LED on the patterned substrate was $14\%$ higher than that on the conventional substrate due to the increased extraction efficiency.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.61.1-61.1
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• 2007

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.136.1-136.1
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• 2009

• Proceedings of the Materials Research Society of Korea Conference
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• 2005.05a
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• pp.117-117
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• 2005

• Proceedings of the Materials Research Society of Korea Conference
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• 2000.11a
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• pp.99-99
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• 2000

• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.235.1-235
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• 2003

• Journal of the Korean Vacuum Society
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• v.5 no.2
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• pp.119-126
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• 1996

The effect of the $O_2$ concentration in the sputtering gas mixture, substate temperature and Ar pressure on the structural and optical properties of 3 mol% YSZ and 8 mol% YSZ thin films deposited by RF magnetron sputtering were investigated . The films were observed to have various crystal structures with different compositions in accordance with the type of the target materials. The size of fine grain-like particles decreased wiht increasing the $O_2$ concentration in the sputtering gas in the case of 3mol% YSZ, while it increased in the case of 8 mol% YSZ . However, the average opticla transmission of 8mol% YSZ, despite of thicker thickness. was higher than that of 3 mol% YSZ. Furthermore, the values of refractive index of 3mol% YSZ increased with increasing the $O_2$ concentration in the sputtering gas on the contrary to those of the 8 mol% YSZ. However, the transmission spectra of 8 mol% YSZ films were not strongly influenced by the substrate temperature and Ar pressure, whereas the refractive index of the YSZ films were strongly affected by the sputtering parameters.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.558-561
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• 2001

In this study, the ZnS nanosized thin films were grown by the solution growth technique (SGT), and their structural and optical properties were examined. X-ray diffraction patterns showed that the ZnS thin film obtained in this study had the cubic structure ($\beta$-ZnS). With decreasing growth temperature and decreasing concentration of precursor solution, the surface morphology of film was found to be improved. In particular, this is the first time that the surface morphology dependence of ZnS film grown by SGT on the ammonia concentration is reported. The energy band gaps of samples were shown to vary from 3.69 eV to 3.91 eV, demonstrating that the quantum size effect of SGT grown ZnS is remarkable. Photoluminescence (PL) peaks were observed at the positions corresponding to the lower energy than that to energy band gap, illustrating that the surface states were induced by the ultra-fineness of grains in ZnS films.