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[[abstract]]單晶矽太陽能電池中,其背面會鍍上鈍化介電層降低載子複合機率,而為了將電極與矽基板接觸將所生成的載子導出,所以要將鈍化介電層圖案化開孔。目前用來將介電層圖案化的技術有噴印保護層、噴印蝕刻以及雷射消融法,但是噴印保護層的製程繁瑣,且會有殘留物的問題,而雷射消融法則是會對晶圓表面造成缺陷,對效率都有影響。為了減少成本,縮減繁瑣的製程,雷射背電極燒結法(LFC, Laser Fired Contact)是近年來常被運用在太陽能電池製程的一種方式。雷射背電極燒結法整合了背面鈍化層開孔以及鋁膠燒結的製程,雖然縮短了製程,省下許多時間,但雷射背電極燒結法和雷射消融一樣,會使晶圓表面形成缺陷,對效率產生影響。 本研究利用噴塗的方式將霧化的蝕刻液噴在已鍍上鈍化層的晶圓表面,此蝕刻液為氫氟酸,將鈍化層依照遮罩上的圖案蝕刻開孔。這種方法不會對晶圓表面造成傷害,而且也縮短了噴印保護層的製程,節省許多製程成本。利用噴塗的方式我們可以改變氣流和遮蔽罩大小,進而控制開孔大小。而僅利用氫氟酸蝕刻在基板表面會往外攤開,使開孔周圍有一圈鈍化層厚度漸層,使開孔形貌不佳,本實驗在氫氟酸蝕刻液內添加磷酸,增加蝕刻液的黏度,讓蝕刻液在基板表面可以聚集,不會往外攤開,造成鈍化層厚度漸層,得到較佳的開孔形貌。本實驗利用磷酸比10%氫氟酸=1:10作為蝕刻液,可以將氧化鋁和氮化矽噴塗蝕刻,且孔洞大小與遮罩孔洞大小誤差在10%以內,且厚度漸層小於10μm。
[[abstract]]Aluminum-induced crystallization (AIC) process was used to prepare the cheaper and has large grain poly-silicon films for thin film solar cell. But it is observed that the high density of intragrain defects form in the poly-Si film during AIC process, that will enhance the carrier recombination probability, and such that directly influence the efficiency of solar cell. To solve this problem, we use TEM to investigate the nucleation and growth of silicon grain in a series of time length of AIC process. Using sputtering method, 300 nm poly-Al layer was deposited onto glass substrate, then the sputtering chamber was exposed to atmosphere for 2 min in order to obtain a native oxide layer. Finally 600 nm amorphous silicon layer was deposited using a sputter, to get Al/Al2O3/α-Si stacking structure. After deposition processes, ...
[[abstract]]Abstract Phosphoric acid and boric acid were used as low cost, nontoxic n-type and p-type doping sources for silicon solar cells. In this research, we coated dilute phosphoric acid and boric acid on silicon wafer by ultrasonic spray coating method without any additional complicated vacuum system. Furthermore, a designed pattern diffusion area can be obtained by using an easily removed mask. After these two acids spraying on, the n-type and p-type patterned area can be driven-in at just one annealing process in air. The sheet resistance of the n-type and p-type doping area can be controlled by spraying time and annealing temperature. In phosphorus doping, sheet resistance ranging from 28 to 125Ω/□ were achieved. In boron doping, sheet resistance from 30 to 125Ω/□ could be acquired. The n-type and p-type doping fabricatio...
[[abstract]]Grow of thin-film polycrystalline Si (pc-Si) as a seed layer has been shown to be useful for further epitaxially thickening absorber layers for thin film solar cell. In order to effectively reduce the cost of seed layer, we propose in this thesis to deposit pc-Si via AIC process on a cheaper foreign substrate such as ceramics or glass which has better mechanical strength. The solar cell fabricated with this proposed process can be potentially used as bricks in the wall of building in the future.Efficiency of pc-Si thin film solar cell is strongly dependent of grain size and amount of intragraunalr defect. The grain boundary and intragraunlar defects offer electron-hole recombination sites which lead to degrade the efficiency of thin film pc-Si based solar cell. Thus, defect-free large-grain pc-Si film appears to favor solar...
[[abstract]]Abstract In this paper, the wet-cell which was manufactured by MEMS processes is used for isolating the hydrated, liquid sample from the vacuum environmental of electron microscope. Thus we can observe the native state cell under the electron microscopes which have much higher resolution than optical microscope. Through the images of the above sample which obtained by a BSE mode SEM, we can confirm the liquid is sealed in the wet-cell. However, the image of Chlamydomonas reinhardtii cannot be observed and after the test of attaching cell to the thin film, we understand that the contrast between water and cell are too low to appear. A solution for solving this problem is that replace the water by glycerine to enhance the contrast of image. On the other hand, the images which acquired from TEM bring limited information. This...
[[abstract]]Coherent diffractive imaging (CDI) is a new technique for the structural analysis of materials at a resolution limited by the wavelength of the radiation involved. Due to the strong interaction of electrons with matter and short de Broglie wavelength of electrons, electron CDI offers, in principle, atomic-scale resolution of nano-objects in coherent diffraction experiments. In addition, for nanocrystals, coherent diffraction in Bragg geometry allows for the recovery of a three-dimensional (3D) structure of the sample using an angular range of crystal tilt within a few degrees. In this thesis, a detailed theoretical and experimental investigation of the electron CDI technique is presented. The well-known nanocrystals of MgO smoke were used as a test nano-object. For diffraction experiments, we used a highly coherent illumina...
[[abstract]]摘要 由於弱相位物的低影像對比,造成生物試片或是輕元素材料試片不易在穿透式電子顯微鏡下觀察,雖然在傳統TEM下可藉著大量的離焦方法來提升影像對比,但會喪失解析度導致影像模糊,故發展靜電式相位板在保有解析度的情況下提升影像上的相位對比。我們的靜電式相位板是由Au/Si3N4/Au/Si3N4/Au五層所構成的單根懸臂樑結構,經由外加電壓的控制,將於相位板內部形成一均勻靜電場,並且改變穿透電子束π/2相位,進而提升影像上的對比。 在2006年,我們的靜電式相位板首先成功的分辨出SiONx與SiO2的介面,並且於2009年間再度提升了鐵蛋白的影像對比,但不論是薄膜式相位板或靜電式相位板,電荷累積皆是目前實驗上所遭遇到的最大問題。在本篇論文中,我們歸納出會導致靜電式相位板電荷累積的三個因素:二次電子的產生、電子束與Si3N4的作用以及汙染物的生成, 並針對這三種因素提出方法來一一改善,務求使電荷累積的問題不再產生。
[[abstract]]摘要 在1991年,瑞士科學家Grätzel首次將金屬釕有機配合物作為染料,吸附在採用高比表面積的二氧化鈦奈米結構多孔膜上,染料敏化太陽能電池光電轉換效率有大幅的提升,其低成本、製作簡單、不需昂貴設備等優點,吸引了眾多科學家投入研究行列,同年,奈米碳管被Iijima發現,由於其特殊的幾何結構,造就了擁有優異的物化特性,被廣泛應用在許多領域中,其中良好的導電性、大的長徑比與高穩定性等材料性質,可以被引入至染料敏化太陽能電池的奈米顆粒二氧化鈦中,試圖改善奈米顆粒薄膜的電性。 目前會降低並限制染料敏化太陽能電池光電轉換效率的原因,主要是發生於當吸附在奈米顆粒的染料分子受太陽光激發後,將電子注入至較低能級的二氧化鈦奈米顆粒中進行電子傳遞,此傳輸期間電子會因為二氧化鈦顆粒間晶界的阻礙和不定向的傳輸路徑,導致電子容易與缺電子的染料或電解液進行再複合,而限制了太陽能電池的光電轉換效率,因此將奈米碳管引入提供一個電子傳輸的路徑,增加二氧化鈦膜匯集與傳輸電子的能力以及減少電子再複合機率與增加電子在二氧化鈦膜中的生命期。 在本論文中,主要研究將奈米碳管陣列應用於二氧化鈦電極對染料敏化太陽能電池效率所產生的影響。我們成功以Thermal CVD系統直接成長奈米碳管在透明導電玻璃上,經過實驗發現,通入0.3sccm流量的氧氣,有最佳石墨化程度的奈米碳管,但因為光穿透率的緣故,我們將重新定義奈米碳管圖形,隨後再完整包覆二氧化鈦顆粒於奈米碳管,組裝成元件效率量測結果顯示,當50μm大小陣列效率為最高,而IPCE測試結果也顯示與光電轉換效率有相同的趨勢,最後再經由EIS分析,驗證出奈米碳管在其中所扮演的角色為快速傳輸電子與減少電子再複合機率,因此此實驗結果將提供往後用Thermal CVD 成長奈米碳管在玻璃基板元件的製程。
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