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Synthesis and Optoelectronic Properties of Two-dimensional Transition Metal Dichalcogenides.

紀錄類型:	書目-語言資料,手稿 : Monograph/item
正題名/作者:	Synthesis and Optoelectronic Properties of Two-dimensional Transition Metal Dichalcogenides./
作者:	Bilgin, Ismail.
面頁冊數:	1 online resource (137 pages)
附註:	Source: Dissertation Abstracts International, Volume: 78-09(E), Section: B.
標題:	Nanoscience. -
電子資源:	click for full text (PQDT)
ISBN:	9781369759921

Synthesis and Optoelectronic Properties of Two-dimensional Transition Metal Dichalcogenides.
Bilgin, Ismail.

Synthesis and Optoelectronic Properties of Two-dimensional Transition Metal Dichalcogenides. - 1 online resource (137 pages)

Source: Dissertation Abstracts International, Volume: 78-09(E), Section: B.

Thesis (Ph.D.)--Northeastern University, 2017.

Includes bibliographical references

Graphene, the first 2D layered material, has had an enormous impact on the field of nanomaterials. It has been demonstrated that graphene has remarkable mechanical, electronic and optical properties such as high electrical conductivity, broad band absorption of light etc. However, graphene does not fulfill all the scientific requirements. Due to its zero-band gap, there are limited applications in optoelectronics. To overcome graphene's shortcoming, researchers have recently started to explore other 2-dimensional materials such as metal oxides, transition metal dichalcogenides, and hexagonal boron nitrides.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9781369759921Subjects--Topical Terms:

632473
Nanoscience.
Index Terms--Genre/Form:

554714
Electronic books.

Synthesis and Optoelectronic Properties of Two-dimensional Transition Metal Dichalcogenides.
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245 1 0 $a Synthesis and Optoelectronic Properties of Two-dimensional Transition Metal Dichalcogenides.
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300 $a 1 online resource (137 pages)
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500 $a Source: Dissertation Abstracts International, Volume: 78-09(E), Section: B.
500 $a Adviser: Swastik Kar.
502 $a Thesis (Ph.D.)--Northeastern University, 2017.
504 $a Includes bibliographical references
520 $a Graphene, the first 2D layered material, has had an enormous impact on the field of nanomaterials. It has been demonstrated that graphene has remarkable mechanical, electronic and optical properties such as high electrical conductivity, broad band absorption of light etc. However, graphene does not fulfill all the scientific requirements. Due to its zero-band gap, there are limited applications in optoelectronics. To overcome graphene's shortcoming, researchers have recently started to explore other 2-dimensional materials such as metal oxides, transition metal dichalcogenides, and hexagonal boron nitrides.
520 $a Among the 2D materials, transition metal dichalcogenides (such as MoS 2, MoSe2, WS2, WSe2) get more attention due to their tunable optical band gaps. It has been shown that these TMDs go from indirect to direct band gap as the layer count goes from bulk to monolayer, which is one of the requirements of optoelectronic device applications.
520 $a Since these materials are layered, it can be mechanically exfoliated easily. However, large area and highly crystalline structures are required to observe optical and electronic properties, as well as to make these viable for commercial applications. In my research, I have developed a new synthesis method, called vapor phase chalcogenization, by using MoO2 or WO 2 as a precursor unlike conventionally use Mo, W and MoO3, WO3 powders. With this method, we eliminated the chemical reaction process to one step with less oxygen content in the reaction. The quality of the grown samples is clearly observed by Raman, Photoluminescence, and Photocurrent Spectroscopy., and further analyzed by Transmission Electron Microscopy (TEM). For example, we have reported, for the first time, two distinctly new phonon processes in 2D MoS2 at 285 cm-1 and 487 cm-1. The ultra-high, optoelectronic-grade crystalline quality of MoS2 sample could be also observed through photocurrent spectroscopy, which clearly reveal excitonic states at room temperature. I further studied temperature dependent binding energies of excitons and quasiparticle band gap of MoS2.
520 $a In my second work, I have extended my research to another 2D material, molybdenum diselinide (MoSe2), which is more favorable for solar cell applications due to its optical band gap range. We have observed detailed Raman processes of mono and few layer of MoSe2. which some of them are previously not explained experimentally and theoretically. I further studied excitation energy dependence of the MoSe2 Raman spectrum.
520 $a Finally, creating artificially-stacked and in-plane 2D heterostructures has also opened a new research field for designing new materials. Building these materials also requires clean interfaces, and creating atomically-controlled van der waals (vdW) heterostructure is still challenging. We have synthesized rotationally aligned vertical MoS2-MoSe2 heterostrucutres to investigates the unexplored physical properties of these materials.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Nanoscience. $3 632473
650 4 $a Nanotechnology. $3 557660
655 7 $a Electronic books. $2 local $3 554714
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690 $a 0652
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a Northeastern University. $b Physics. $3 1186941
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10271752 $z click for full text (PQDT)