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Surface and interfacial study of atomic layer deposited $Al_{2}O_{3}$ on $MoTe_{2}$ and $WTe_{2}$
| Content Provider | Scilit |
|---|---|
| Author | Zhu, Hui Addou, Rafik Wang, Qingxiao Nie, Yifan Cho, Kj Kim, Moon J. Wallace, Robert M. |
| Copyright Year | 2019 |
| Description | Journal: Nanotechnology The atomic layer deposition of high-k dielectrics could serve as an efficient barrier against moisture and $O_{2}$ adsorption. Such a barrier is highly needed for $MoTe_{2}$ and $WTe_{2}$ transition metal dichalcogenides (TMDs) because of the poor structural stability and the fast oxidization in ambient air. In-situ X-ray photoelectron spectroscopy and ex-situ atomic force microscopy (AFM) and scanning transmission electron microscopy (STEM) were employed to report a comparative study between the growth of $Al_{2}O_{3}$ on $MoTe_{2}$ and $WTe_{2}$ by means of traditional thermal atomic layer deposition (ALD) and plasma enhanced ALD (PEALD). Similar to what has been observed on other 2D materials such as $MoS_{2}$ and Graphene,the thermal ALD results in an islanding growth of $Al_{2}O_{3}$ on $MoTe_{2}$ due to the dearth of dangling bonds, while a uniform coverage of $Al_{2}O_{3}$ on $WTe_{2}$ likely contributed to the high concentration of intrinsic structural defects. The PEALD behavior is consistent between $MoTe_{2}$ and $WTe_{2}$ providing a conformal and linear growth rate (~0.08 nm/cycle), which correlates with the creation of Te-O and metal-O nucleation sites. However, a thin layer of interfacial Mo or W oxides gradually forms, resulting from the plasma-induced damage in the topmost (1-2) layers. Attempts to enhance the $Al_{2}O_{3}/MoTe_{2}$ interfacial quality by physically evaporating an $Al_{2}O_{3}$ seed layer are investigated as well. However, the evaporated $Al_{2}O_{3}$ process causes thermal damage on $MoTe_{2}$, necessitating a "gentle" ALD technique for the surface passivation. |
| Related Links | https://iopscience.iop.org/article/10.1088/1361-6528/ab4e44/pdf |
| ISSN | 09574484 |
| e-ISSN | 13616528 |
| DOI | 10.1088/1361-6528/ab4e44 |
| Journal | Nanotechnology |
| Issue Number | 5 |
| Volume Number | 31 |
| Language | English |
| Publisher | IOP Publishing |
| Publisher Date | 2019-10-16 |
| Access Restriction | Open |
| Subject Keyword | Journal: Nanotechnology Metallurgy and Metallurgical Engineering |
| Content Type | Text |
| Resource Type | Article |
| Subject | Chemistry Nanoscience and Nanotechnology Mechanics of Materials Mechanical Engineering Bioengineering Electrical and Electronic Engineering |
