2026-09-19T07:44:18Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/1518942023-08-24T03:24:34Zcom_1721.1_7582com_1721.1_7581col_1721.1_131023
Kim, Jeehwan
Lee, Doyoon
Massachusetts Institute of Technology. Department of Mechanical Engineering
2023-08-23T16:17:13Z
2023-08-23T16:17:13Z
2023-06
2023-07-19T18:45:23.475Z
https://hdl.handle.net/1721.1/151894
0000-0003-4355-8146
Two-dimensional (2D) transition metal dichalcogenides (TMDs) and their heterostructures have been widely studied for next-generation electronics. However, the following critical challenges have hindered them from their commercialization: 1) precise layer control during their growth, 2) maintaining single crystallinity at wafer-scale, and 3) inevitable transfer-process to fabricate heterostructure for various next-generation applications such as spintronics, valleytronics, and optoelectronics.
This thesis introduces a confined-growth technique that can overcome the aforementioned hurdles simultaneously by introducing a geometric SiO₂ mask that has growth selectivity from the underlying substrate. As micrometer-scale SiO₂ trenches reduce the growth duration substantially, single-domain WSe₂ and MoS₂ arrays are obtained on an arbitrary substrate at wafer-scale by filling the trenches before the second layer of nuclei is introduced, thus enabling layer-by-layer growth without requiring epitaxial seeding.
In addition, subsequent MoS₂ growth on the WSe₂ arrays yields MoS₂/WSe₂ heterostructures. Therefore, we for the first time demonstrate single-domain TMDs arrays and their heterostructures at wafer-scale with controllable thickness, which of performances are comparable to that fabricated from TMDs flake. This confined-growth technique not only can overcome key obstacles of 2D materials, but also provide a platform with great potential for next-generation 2D-material-based applications.
S.M.
Massachusetts Institute of Technology
In Copyright - Educational Use Permitted
Copyright retained by author(s)
https://rightsstatements.org/page/InC-EDU/1.0/
Layer-by-Layer Single-crystal Two-dimensional Material Growth by Geometric Confinement
Thesis
application/pdf
Master
Master of Science in Mechanical Engineering
Publication
unknown
unknown
<Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="a1fe6989-b54c-4d3f-95d1-bab322e6e7f8">
<Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type>
<Title>Layer-by-Layer Single-crystal Two-dimensional Material Growth by Geometric Confinement</Title>
<PublishedIn>
<Publication>
</Publication>
</PublishedIn>
<PublicationDate>2023-06</PublicationDate>
<Authors>
<Author>
<DisplayName>Lee, Doyoon</DisplayName>
<Affiliation>
<OrgUnit>
</OrgUnit>
</Affiliation>
</Author>
</Authors>
<Editors>
</Editors>
<Publishers>
<Publisher>
<DisplayName>Massachusetts Institute of Technology</DisplayName>
<OrgUnit />
</Publisher>
</Publishers>
<License>https://rightsstatements.org/page/InC-EDU/1.0/</License>
<Abstract>Two-dimensional (2D) transition metal dichalcogenides (TMDs) and their heterostructures have been widely studied for next-generation electronics. However, the following critical challenges have hindered them from their commercialization: 1) precise layer control during their growth, 2) maintaining single crystallinity at wafer-scale, and 3) inevitable transfer-process to fabricate heterostructure for various next-generation applications such as spintronics, valleytronics, and optoelectronics.
This thesis introduces a confined-growth technique that can overcome the aforementioned hurdles simultaneously by introducing a geometric SiO₂ mask that has growth selectivity from the underlying substrate. As micrometer-scale SiO₂ trenches reduce the growth duration substantially, single-domain WSe₂ and MoS₂ arrays are obtained on an arbitrary substrate at wafer-scale by filling the trenches before the second layer of nuclei is introduced, thus enabling layer-by-layer growth without requiring epitaxial seeding.
In addition, subsequent MoS₂ growth on the WSe₂ arrays yields MoS₂/WSe₂ heterostructures. Therefore, we for the first time demonstrate single-domain TMDs arrays and their heterostructures at wafer-scale with controllable thickness, which of performances are comparable to that fabricated from TMDs flake. This confined-growth technique not only can overcome key obstacles of 2D materials, but also provide a platform with great potential for next-generation 2D-material-based applications.</Abstract>
<Access xmlns="http://purl.org/coar/access_right"
>
</Access>
</Publication>