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  • 學位論文

高效能及高穩定之二硫化鉬光偵測器

Air-Stable and High-Performance MoS2 Phototransistor by Self-Encapsulated Photoactive Material

指導教授 : 梁啟德
共同指導教授 : 陳俊維(Chun-Wei Chen)
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摘要


二硫化鉬是一種層與層之間只靠凡德瓦力來維持晶體形態的層狀結構材料也同時是其中一種二維材料。二硫化鉬是一個有能隙的二維材料,相較於石墨烯缺乏能隙,二硫化鉬元件因此能夠達到低暗電流而能有較高的光電增益。同時二硫化鉬可以藉由調整層數多寡來改變能隙,當層數逐漸下降到單層時,能隙會從1.2eV逐漸變大到1.8eV,且從非直接能隙變成直接能隙。相較於古典的半導體材料,二硫化鉬的可饒性和易製造等特性提供了光電元件額外的好處。這也說明了直接能隙的單層二硫化鉬對於光電元件來說是一個具有前瞻性的材料。然而單層二硫化鉬的光學性質和電性可以藉由控制摻雜進而來調整,因此若能精準控制單層二硫化鉬摻雜程度就可以精確調控二硫化鉬光學性質和電性,進而讓單層二硫化鉬光電元件性能可以達到最好。單層二硫化鉬在大氣環境下會因為吸附空氣中的水分子和氧分子進而導致元件性能下降,因此如何克服這個問題對於製作出性能優異的元件是一個重要關鍵。 在本研究中,我們將選擇低氧化鈦來作為元件鈍化層和光敏化材料。在文中的第一個部分我們將單層二硫化鉬電晶體表面鍍上低氧化鈦,我們會發現到可以做為單層二硫化鉬電晶體的良好鈍化層並且我們也發現到了低氧化鈦會造成單層二硫化鉬電晶體n型摻雜。 而在文章的第二部分,我們利用“光”來讓低氧化鈦摻雜單層二硫化鉬電晶體,我們發現利用此種摻雜方式可以讓我們精確的控制單層二硫化鉬的被摻雜程度,同時我們也發現此種摻雜方式為調致摻雜。在文章的最後我們發現到此種利用光來摻雜的方式可以用來當作元件偵測光強度的依據,再加上低氧化鈦可以當作單層二硫化鉬電晶體的鈍化層,使得我們的元件即使是在大氣環境下也可以穩定且精準的量測,進而讓我們可以做出高效能及高穩定的單層二硫化鉬光偵測器。

並列摘要


Crystals of MoS2 are composed of vertically stacked, weakly interacting layers held together by van der Waals interactions. MoS2 is a material, which has a bandgap. In contrast to graphene, which does not have a bandgap in its pristine form, MoS2-based device can achieve low dark current and high photoresponsivity. MoS2 can tune its bandgap by modifying its layer thickness. Bulk MoS2 has an indirect bandgap of 1.2eV crosses over to a direct bandgap of ∼1.8 eV when the thickness is down to monolayer. Compared with classical semiconductors, MoS2 can offer additional advantages for optoelectronics because of their easy processing, mechanical flexibility, etc. Thus, the single-layer MoS2 suggests that it could be a promising material for optoelectronic applications. However, the optical properties and electronic properties in single-layer MoS2 can be manipulated by controlling doping. Thus, we can precisely tune both the optical and electronic properties in single-layer MoS2 by precisely controlling doping level. Therefore, we can optimize the optoelectronic device performance. Because single-layer MoS2 transistor would absorb oxygen and water in air, it would cause device performance degradation. Therefore, air-stability becomes a crucial issue for making high performance single-layer MoS2 based optoelectronics. In this work, we induced titanium sub-oxide as a photoactive material and simultaneously a passivation layer for single-layer MoS2 transistor, which prevented single-layer MoS2 from oxygen and water in the ambient. In first part of this work (chapter3), the sol-gel TiOx were spin-coated on top of single-layer MoS2 transistor and we found that TiOx thin film could act as a good passivation layer for single-layer MoS2 transistor and simultaneously cause n-type doping in single-layer MoS2 transistor. Next, In second part of this work, we induced a novel doping technique, which doped single-layer MoS2 transistor by using light. This method could precisely control single-layer MoS2 doping level and it would be a modulation doping. In the final part of the article, we found that this doping technique could act as a reference for detect light intensity and combined with the property of passivation layer to fabricate air-stable and high performance single-layer MoS2 photodetector.

參考文獻


58. Lingming Yang, Kausik Majumdar, Han Liu, Yuchen Du, Heng Wu, Michael Hatzistergos, P. Y. Hung, Robert Tieckelmann, Wilman Tsai, Chris Hobbs, Peide D. Ye. Chloride Molecular Doping Technique on 2D Materials: WS2 and MoS2. Nano Lett. 2014, 14 (11), 6275–6280.
80. Lingming Yang, Kausik Majumdar, Han Liu, Yuchen Du, Heng Wu, Michael Hatzistergos, P. Y. Hung, Robert Tieckelmann, Wilman Tsai, Chris Hobbs, Peide D. Ye. Chloride Molecular Doping Technique on 2D Materials: WS2 and MoS2. Nano Lett. 2014, 14 (11), 6275–6280.
24. Junhong Na, Min-Kyu Joo, Minju Shin, Junghwan Huh, Jae-Sung Kim, Mingxing Piao, Jun-Eon Jin, Ho-Kyun Jang, Hyung Jong Choi, Joon Hyung Shim and Gyu-Tae Kim. Low-frequency noise in multilayer MoS2 field effect transistors: the effect of high-k passivation. Nanoscale 2014, 6, 433.
46. Junhong Na, Min-Kyu Joo, Minju Shin, Junghwan Huh, Jae-Sung Kim, Mingxing Piao, Jun-Eon Jin, Ho-Kyun Jang, Hyung Jong Choi, Joon Hyung Shim and Gyu-Tae Kim. Low-frequency noise in multilayer MoS2 fieldeffect transistors: the effect of high-k passivation. Nanoscale, 2014, 6, 433.
45. Yung-Chang Lin , Dumitru O. Dumcenco , Hannu-Pekka Komsa , Yoshiko Niimi ,

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