• 제목/요약/키워드: Laser damage removal

검색결과 15건 처리시간 0.143초

Effects of Laser Doping on Selective Emitter Si Solar Cells (레이져를 이용한 도핑 특성과 선택적 도핑 에미터 실리콘 태양전지의 제작)

  • Park, Sungeun;Park, Hyomin;Nam, Junggyu;Yang, JungYup;Lee, Dongho;Min, Byoung Koun;Kim, Kyung Nam;Park, Se Jin;Lee, Hae-Seok;Kim, Donghwan;Kang, Yoonmook;Kim, Dongseop
    • Current Photovoltaic Research
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    • 제4권2호
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    • pp.54-58
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    • 2016
  • Laser-doped selective emitter process requires dopant source deposition, spin-on-glass, and is able to form selective emitter through SiNx layer by laser irradiation on desired locations. However, after laser doping process, the remaining dopant layer needs to be washed out. Laser-induced melting of pre-deposited impurity doping is a precise selective doping method minimizing addition of process steps. In this study, we introduce a novel scheme for fabricating highly efficient selective emitter solar cell by laser doping. During this process, laser induced damage induces front contact destabilization due to the hindrance of silver nucleation even though laser doping has a potential of commercialization with simple process concept. When the laser induced damage is effectively removed using solution etch back process, the disadvantage of laser doping was effectively removed. The devices fabricated using laser doping scheme power conversion efficiency was significantly improved about 1% abs. after removal the laser damages.

Removal of Laser Damage in Electrode Formed by Plating in Crystalline Silicon Solar Cells (결정질 실리콘 태양전지에서 도금을 이용한 전극 형성 시 발생되는 레이저 손상 제거)

  • Jeong, Myeong Sang;Kang, Min Gu;Lee, Jeong In;Song, Hee-eun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • 제29권6호
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    • pp.370-375
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    • 2016
  • In this paper, we investigated the electrical properties of crystalline silicon solar cell fabricated with Ni/Cu/Ag plating. The laser process was used to ablate silicon nitride layer as well as to form the selective emitter. Phosphoric acid layer was spin-coated to prevent damage caused by laser and formed selective emitter during laser process. As a result, the contact resistance was decreased by lower sheet resistance in electrode region. Low sheet resistance was obtained by increasing laser current, but efficiency and open circuit voltage were decreased by damage on the wafer surface. KOH treatment was used to remove the laser damage on the silicon surface prior to metalization of the front electrode by Ni/Cu/Ag plating. Ni and Cu were plated for each 4 minutes and 16 minutes and very thin layer of Ag with $1{\mu}m$ thickness was plated onto Ni/Cu electrode for 30 seconds to prevent oxidation of the electrode. The silicon solar cells with KOH treatment showed the 0.2% improved efficiency compared to those without treatment.

Characteristics of Si3N4 Laser Assisted Machining according to the Laser Power and Feed Rate

  • Kim, Jong-Do;Lee, Su-Jin;Suh, Jeong
    • Journal of Advanced Marine Engineering and Technology
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    • 제34권7호
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    • pp.963-970
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    • 2010
  • This study makes an estimate of the laser-assisted machining (LAM) of an economically viable process for manufacturing precision silicon nitride ceramic parts using a high-power diode laser (HPDL). The surface is locally heated by an intense laser source prior to material removal, and the resulting softening and damage of the workpiece surface simplify the machining of the ceramics. The most important advantage of LAM is its ability to produce much better workpiece surface quality compared to conventional machining. Also important are its larger material removal rates and longer tool life. The cutting force and surface temperature were measured on-line using a pyrometer and a dynamometer, respectively. Tool wear, chips and the surface of the workpiece were measured using optical microscopy, and the surface and fractured cross-section of $Si_3N_4$ were measured by SEM. During the LAM process, the cutting force and tool wear were reduced and oxidation of the machined surface was increased according to the increase in the laser power. Moreover, the more the feed rate increased, the more the cutting force and tool wear increased.

Experimental Study for Removing Artificial Patinas of Bronze Sculpture by Nd:YAG Laser Cleaning System (청동 조형물의 인공 파티나 제거를 위한 Nd:YAG 레이저 적용 실험 연구)

  • Park, Chang-Su;Cho, Nam-Chul
    • Journal of the Korean institute of surface engineering
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    • 제46권5호
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    • pp.197-207
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    • 2013
  • In the midst of increasing importance of modern cultural assets, especially, most modern bronze objects are exposed to outdoor environment, and as the objects are corroded steadily due to environmental factors the objects lost their original colors on the surface. We performed artificial patinas on the bronze sample per each color of red, black and green and checked cuprite and tenorite which are detected from actual bronze corrosion by analyzing the components. In addition, we applied the existing corrosion removal methods of grinder and sand blaster on a similar sample of bronze mirror per injection pressure and performed comparative analysis on the result with Nd:YAG laser. As a result of Nd:YAG laser cleaning artificial patina from bronze samples, all of the patinas were removed by laser wavelength 1064 nm better than 532 nm. Upon applying to a similar sample of bronze mirror, the artificial patina could be selectively removed from substrates without surface damage when Nd:YAG laser was conducted other than the existing removal method, and so it showed the possibility of application.

Carbon dioxide LASER-aided management of oral mucosal diseases (이산화탄소(CO2) 레이저로 치료하면 좋은 구강점막질환)

  • Byun, Jin-Seok
    • The Journal of the Korean dental association
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    • 제56권7호
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    • pp.391-397
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    • 2018
  • Mess removal, electrocoagulation, cryosurgery are conventional methods in the treatment of various oral mucosal diseases. However, there are several problems or complication during or after surgery using conventional tools. Recently, LASER gradually become useful tool in the surgery of oral mucosal diseases. Of the LASER, carbon dioxide-mediated LASER is widely used one. Carbon dioxide LASER has many advantages such as good bleeding control, decreased damage to adjacent tissue, decreased pain and swelling, reduced scar formation, even bacteriocidal effects. In this reports, the author describe pros and cons of LASER, especially focused on carbon dioxide, and shed light on the field of LASER application in treatment of various oral mucosal diseases.

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Laser via drilling technology for the EWT solar cell (EWT 태양전지 제작을 위한 레이저 미세 관통홀 가공 기술)

  • Lee, Hong-Gu;Seo, Se-Young;Hyun, Deoc-Hwan;Lee, Yong-Wha;Kim, Gang-Il;Jung, Woo-Won;Lee, Ah-Reum;Cho, Jaee-Ock
    • Journal of the Korean Solar Energy Society
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    • 제31권4호
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    • pp.103-111
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    • 2011
  • Laser drilling of vias is the one of key technologies in developing Emitter-Wrap Through(EWT) solar cell which is particularly attractive due to the use of industrial processing and common solar grade p-type silicon materials. While alternative economically feasible drilling process is not available to date, the processing time and laser induced damage should be as small as possible in this process. This paper provides an overview on various factors that should be considered in using the laser via drilling technology for developing highly efficient and industrially applicable EWT solar cells.

Dry-etch Characteristics of InP/InGaAsP Photonic Crystal Structure (InP/InGaAsP 광자결정 구조 제작을 위한 건식 식각 특성)

  • Lee, Ji-Myon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • 제17권12호
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    • pp.1271-1276
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    • 2004
  • Two-dimensionally arrayed nanocolumn lattices were fabricated by using double-exposure laser holographic method. The hexagonal lattice was formed by rotating the sample with 60 degree while the square lattice by 90 degree before the second laser-exposure. The reactive ion etching for a typical time of 30 min using CH$_4$/H$_2$ plasma enhanced the aspect-ratio by more than 1.5 with a slight increase of the bottom width of columns. The etch-damage was observed by photoluminescence (PL) spectroscopy which was removed by the wet chemical etching using HBr/$H_2O$$_2$/$H_2O$ solution, leading into the enhanced PL intensities of the PCs.

Characteristics of Damage on Photosensor Irradiated by Intense Illumination : Thermal Diffusion Model (고섬광에 노출된 광센서의 손상 특성 : 열확산 모델)

  • Kwon, Chan-Ho;Shin, Myeong-Suk;Hwang, Hyon-Seok;Kim, Hong-Lae;Kim, Seong-Shik;Park, Min-Kyu
    • Journal of the Korea Institute of Military Science and Technology
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    • 제15권2호
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    • pp.201-207
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    • 2012
  • Pulsed lasers at the 613 nm and 1064 nm wavelengths on nanoseconds have been utilized to characterize the damage on Si photodiode exposed to intense illumination. Morphological damages and structural changes at sites on the photodiode irradiated during microseconds of laser pulses were analyzed by FE-SEM images and XRD patterns, respectively. The removal of oxide coating, ripple, melting marks, ridges, and crater on photodiodes were definitely observed in order of increasing the pulse intensities generated above the damage threshold. Then, the degradation in photosensitivity of the Si photodiode irradiated by high power density pulses was measured as a function of laser irradiation time at the various wavelengths. The free charge carrier and thermal diffusion mechanisms could have been invoked to characterize the damage. The relative photosensitivity data calculated using the thermal diffusion model proposed in this paper have been compared with the experimental data irradiated above the damage threshold.

Characteristics of Double Texturization by Laser and Reactive Ion Etching for Crystalline Silicon Solar Cell (레이저를 이용한 결정질 실리콘 태양전지의 Double Texturing 제조 및 특성)

  • Kwon, Jun-Young;Han, Kyu-Min;Choi, Sung-Jin;Song, Hee-Eun;Yoo, Jin-Soo;Yoo, Kwon-Jong;Kim, Nam-Soo
    • Korean Journal of Materials Research
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    • 제20권12호
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    • pp.649-653
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    • 2010
  • In this paper, double texturization of multi crystalline silicon solar cells was studied with laser and reactive ion etching (RIE). In the case of multi crystalline silicon wafers, chemical etching has problems in producing a uniform surface texture. Thus various etching methods such as laser and dry texturization have been studied for multi crystalline silicon wafers. In this study, laser texturization with an Nd:$YVO_4$ green laser was performed first to get the proper hole spacing and $300{\mu}m$ was found to be the most proper value. Laser texturization on crystalline silicon wafers was followed by damage removal in acid solution and RIE to achieve double texturization. This study showed that double texturization on multi crystalline silicon wafers with laser firing and RIE resulted in lower reflectance, higher quantum yield and better efficiency than that process without RIE. However, RIE formed sharp structures on the silicon wafer surfaces, which resulted in 0.8% decrease of fill factor at solar cell characterization. While chemical etching makes it difficult to obtain a uniform surface texture for multi crystalline silicon solar cells, the process of double texturization with laser and RIE yields a uniform surface structure, diminished reflectance, and improved efficiency. This finding lays the foundation for the study of low-cost, high efficiency multi crystalline silicon solar cells.

The Effects of Nd:YAG Laser Irradiation on the Root Surface;A Scanning Electron Microscopic Study (Nd:YAG 레이저 조사시 치근면에 미치는 효과에 관한 주사전자현미경적 연구)

  • Lee, Su-Jeong;Kim, Soo-Ah;Seo, Seok-Ran;Kim, Hyung-Seop
    • Journal of Periodontal and Implant Science
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    • 제27권3호
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    • pp.495-514
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    • 1997
  • The purpose of this study was to evaluate the in vitro effects of Nd:YAG laser irradiation on removal of a root surface smear layer after root planing in comparison with Tetracycline HCl. The 60 extracted human teeth due to severe periodontal disease were vigorously scaled and root planed with Gracey curet. Thirty specimen($5{\times}5{\times}2mm$) were obtained from root planed surface of 30 human teeth and assigned randomly to one of three groups : root planed group(5 specimen), Tetracycline HCI group(5 specimen, burnished for 5 minutes), and Nd:YAG laser group(25 specimen, German Dental Laser, Fotona Twinlight). Nd:YAG laser group was divided into 4 subgroups according to power of 1W, 1.5W, 2W, 3W at frequency to 10Hz. The specimen were then fixed, and examed by Scanning electron microscopic study. 30 of 60 human teeth used to measurement of the intrapulpal temperature rise during laser irradiation. Laser-irradiated surface exhibited various surface texture from relative flat surface to irregular surface with patent dentinal tubules of various shape and size. In some area, the root surface alteration which are carbonization, pit and crater formation and melting and resolidification were observed. The number of exposed dentinal tubules per unit($100_{\mu}m^2$) on tetracycline HCI group was more than that in the laser group below 1.5W of power(150mJ/pulse) and was significantly less than that in laser group above 2W of power(200mJ/pulse)(P<0.OOl). As power increased the intrapulpal temperature rise also increased. The result suggested that the parameter which effectively remove root surface smear layer than tetracycline HCI may cause thermal damage to pulp and root surface alteration result from laser exposure would indicate need for additional instrumentation. Thus, Nd:YAG laser irradiation in these parameter may not be appropriate for clinical use as adjunct to conventional periodontal therapy.

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