• Applied Microscopy
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• v.46 no.3
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• pp.155-159
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• 2016

This paper analyses the relationship between the distribution of a dielectric layer on the apex of a metal field electron emitter and the distribution of electron emission. Emitters were prepared by coating a tungsten emitter with a layer of epoxylite resin. A high-resolution scanning electron microscope was used to monitor the emitter profile and measure the coating thickness. Field electron microscope studies of the emission current distribution from these composite emitters (Tungsten-Clark Electromedical Instruments Epoxylite resin [Tungsten/CEI-resin emitter]) have been carried out. Two forms of image have been observed: bright single-spot images, thought to be associated with a smooth substrate and a uniform dielectric layer; and multi-spot images, though to be associated with irregularity in the substrate or the dielectric layer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.7
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• pp.634-639
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• 2002

Using laser ablation technique carbon thin films were deposited on Si(100) substrate as a function of substrate temperature. In this study, the surface morphologic, structural and field emission properties of these carbon thin films were investigated using Raman spectroscopy, scanning electron microscopy, and a diode technique, respectively. With increasing of the substrate temperature, the surface morphologies were changed significantly. Moreover, the intensity of D-band and the full width at half maximum of these bands were dependent on substrate temperatures. As the substrate temperature was increased, the field emission properties were improved. As the result, we find that the field emission properties of the films were changed significantly with the substrate temperature and structural features of carbon than films.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.239.1-239.1
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• 2005

• Applied Microscopy
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• v.45 no.4
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• pp.214-217
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• 2015

This study introduces metal coating as an effective sample preparation method to remove charge-up caused by the shadow effect during field emission scanning electron microscope (FE-SEM) analysis of dynamic structured samples. During a FE-SEM analysis, charge-up occurs when the primary electrons (input electrons) that scan the specimens are not equal to the output electrons (secondary electrons, backscattered electrons, auger electrons, etc.) generated from the specimens. To remove charge-up, a metal layer of Pt, Au or Pd is applied on the surface of the sample. However, in some cases, charge-up still occurs due to the shadow effect. This study developed a coating method that effectively removes charge-up. By creating a converted sample stage capable of simultaneous tilt and rotation, the shadow effect was successfully removed, and image data without charge-up were obtained.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.147-150
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• 2002

The electron field emission properties of amorphous carbon (a-C) films deposited using a RF magnetron sputtering system have been improved by introducing a simple method of argon plasma treatment at room temperature. Surface morphologies and structural properties of the a-C films were investigated by scanning electron microscopy and Raman spectroscope, respectively. Structural properties and surface morphologies of the a-C films were changed by argon plasma treatment. The emission properties improved with the plasma treatment.

• Applied Microscopy
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• v.43 no.1
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• pp.34-39
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• 2013

Glandular and nonglandular trichomes on the leaf surface of Plectranthus tomentosa were investigated by variable pressure field emission scanning electron microscopy (VP-FESEM). The segments of the plant's leaves were directly mounted without any specimen preparation, and examined at ambient temperature using a variable pressure secondary electron (SE) detector under ca. 15 Pa. Foliar trichomes maintained their shapes and structures without severe surface collapse or charging. The adaxial leaf surface was abundantly covered with different types of trichome. Nonglandular trichomes consisted of a basal cell and a long (up to ca. $300{\mu}m$) stalk. Meanwhile, capitate glandular trichomes had a secretory head and a short or long stalk. Peltate glandular trichomes with globose secretory heads were observed in close contact with the leaf epidermis. Spherical projections on the secretory head showed the secretion process of glandular trichomes. In addition to the trichomes, oval stomata were distributed on the abaxial leaf surface. These results suggest that ambient VP-FESEM can be used to classify the dehydration-sensitive foliar trichomes of succulent plants by SE imaging. At the FESEM resolution, this approach facilitates the rapid and detailed morphological analysis of a variety of trichomes in diverse plant taxa with reduced labor and preparation.

• Applied Microscopy
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• v.52
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• pp.4.1-4.11
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• 2022

Field emission scanning electron microscopy (FESEM) is an essential tool for observing surface details of specimens in a high vacuum. A series of specimen procedures precludes the observations of living organisms, resulting in artifacts. To overcome these problems, Takahiko Hariyama and his colleagues proposed the concept of the "nanosuit" later referred to as "NanoSuit", describing a thin polymer layer placed on organisms to protect them in a high vacuum in 2013. The NanoSuit is formed rapidly by (i) electron beam irradiation, (ii) plasma irradiation, (iii) Tween 20 solution immersion, and (iv) surface shield enhancer (SSE) solution immersion. Without chemical fixation and metal coating, the NanoSuit-formed specimens allowed structural preservation and accurate element detection of insulating, wet specimens at high spatial resolution. NanoSuit-formed larvae were able to resume normal growth following FESEM observation. The method has been employed to observe unfixed and uncoated bacteria, multicellular organisms, and paraffin sections. These results suggest that the NanoSuit can be applied to prolong life in vacuo and overcome the limit of dead imaging of electron microscopy.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.83-83
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• 2012

본 강연에서는 방사광 연X-선 분광현미경학(spectro-microscopy) 중에서, 표면에서 방출되는 광전자를 이용하는 SPEM (Scanning Photoelectron Microscopy)과 PEEM (Photoemission Electron Microscopy)을 소개하고자 한다. SPEM은 입사하는 X-선을 작은 크기로 집속하여 특정의 작은 공간에서 광전자분광학(XPS) 데이터를 얻거나 특정 광전자에너지의 공간분포를 얻게 해주며, PEEM은 입사한 X-선에 의해 발생한 광전자를 전자렌즈 원리로 영상을 맺히게 하여 광전자의 발생 분포를 구하게 한다. 이들은 균일하지 아니한 이종의 표면 연구에 매우 유용한 측정기법들이지만, 그 원리 및 구성은 많은 차이점들을 가지고 있다. 예를 들어, SPEM은 시료를 scanning하면서 XPS에 보다 충실한 타입이고 PEEM은 full field imaging 타입으로 표면변화의 동역학 연구에 강점이 있다. 본 강의에서는 이들 각각의 원리, 장점들에 대해서 설명하고, 활용 예를 제시하고자 한다. 활용 분야에 있어서, SPEM의 경우는 포항가속기연구소의 SPEM으로 수행되었던 DMS, graphene, nano-lithography, OLED, 등 반도체 및 나노 소재, 소자에의 활용에 대한 예를 제시할 것이다. PEEM의 경우는 포항가속기연구소의 응용 예와 박막 형태의 magnetic material에 대한 예들을 제시할 것이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.519-523
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• 2000

Using plasma-enhanced chemical vapor deposition (PECVD), carbon thin film as electron field emitter were fabricated. These carbon thin film were deposited on Si(100) substrate at several RF power. These film were estimated by raman spectroscopy, scanning electron microscopy, and field emission. The field electron emission property of these carbon thin film was estimated by a diode technique. As the result, we observed that the field emission properties of these films were promoted by higher RF power. These results are explained as change of surface morphology and structural properties of carbon thin film

• Applied Microscopy
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• v.47 no.1
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• pp.55-62
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• 2017

This paper describes experiments aimed at characterizing the behavior of field electron emitters fabricated by coating carbon fibers with epoxylite resin. Polyacrylonitrile carbon fibers of type VPR-19, thermally treated at $2,800^{\circ}C$, were used. Each was initially prepared in a "uncoated" state, by standard electro polishing and cleaning techniques, and was then examined in a scanning electron microscope. The fiber was then baked overnight in a field electron microscope (FEM) vacuum chamber. Current-voltage characteristics and FEM images were recorded on the following day or later. The fiber was then removed from the FEM, coated with resin, "cured" by baking, and replaced in the FEM. After another overnight bake, the FEM characterization measurements were repeated. The coated fibers had significantly better performance than uncoated fibers. This confirms the results of earlier experiments, and is thought to be due in part to the formation of a conducting channel in the resin over layer. For the coated fiber, lower voltages were needed to obtain the same emission current. The coated fibers have current-voltage characteristics that show smoother trends, with greater stability and repeatability. No switch-on phenomena were observed. In addition, the emission images on the phosphor-coated FEM screen were more concentrated, and hence brighter.