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1. In situ MOCVD growth and band offsets of Al 2 O 3 dielectric on β-Ga 2 O 3 and β-(Al x Ga 1−x ) 2 O 3 thin films

   https://doi.org/10.1063/5.0104433  

   Bhuiyan, A F ; Meng, Lingyu ; Huang, Hsien-Lien ; Hwang, Jinwoo ; Zhao, Hongping ( October 2022 , Journal of Applied Physics)

   The in situ metalorganic chemical vapor deposition (MOCVD) growth of Al 2 O 3 dielectrics on β-Ga 2 O 3 and β-(Al x Ga 1−x ) 2 O 3 films is investigated as a function of crystal orientations and Al compositions of β-(Al x Ga 1−x ) 2 O 3 films. The interface and film qualities of Al 2 O 3 dielectrics are evaluated by high-resolution x-ray diffraction and scanning transmission electron microscopy imaging, which indicate the growth of high-quality amorphous Al 2 O 3 dielectrics with abrupt interfaces on (010), (100), and [Formula: see text] oriented β-(Al x Ga 1−x ) 2 O 3 films. The surface stoichiometries of Al 2 O 3 deposited on all orientations of β-(Al x Ga 1−x ) 2 O 3 are found to be well maintained with a bandgap energy of 6.91 eV as evaluated by high-resolution x-ray photoelectron spectroscopy, which is consistent with the atomic layer deposited (ALD) Al 2 O 3 dielectrics. The evolution of band offsets at both in situ MOCVD and ex situ ALD deposited Al 2 O 3 /β-(Al x Ga 1−x ) 2 O 3 is determined as a function of Al composition, indicating the influence of the deposition method, orientation, and Al composition of β-(Al x Ga 1−x ) 2 O 3 films on resulting band alignments. Type II band alignments are determined at the MOCVD grown Al 2 O 3 /β-(Al x Ga 1−x ) 2 O 3 interfaces for the (010) and (100) orientations, whereas type I band alignments with relatively low conduction band offsets are observed along the [Formula: see text] orientation. The results from this study on MOCVD growth and band offsets of amorphous Al 2 O 3 deposited on differently oriented β-Ga 2 O 3 and β-(Al x Ga 1−x ) 2 O 3 films will potentially contribute to the design and fabrication of future high-performance β-Ga 2 O 3 and β-(Al x Ga 1−x ) 2 O 3 based transistors using MOCVD in situ deposited Al 2 O 3 as a gate dielectric. 

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2. γ -phase inclusions as common structural defects in alloyed β -(Al x Ga 1−x ) 2 O 3 and doped β -Ga 2 O 3 films

   https://doi.org/10.1063/5.0038861  

   Chang, Celesta S. ; Tanen, Nicholas ; Protasenko, Vladimir ; Asel, Thaddeus J. ; Mou, Shin ; Xing, Huili Grace ; Jena, Debdeep ; Muller, David A. ( May 2021 , APL Materials)
3. MOCVD Epitaxy of Ultrawide Bandgap β-(Al x Ga 1–x ) 2 O 3 with High-Al Composition on (100) β-Ga 2 O 3 Substrates

   https://doi.org/10.1021/acs.cgd.0c00864  

   Anhar Uddin Bhuiyan, A F ; Feng, Zixuan ; Johnson, Jared M. ; Huang, Hsien-Lien ; Hwang, Jinwoo ; Zhao, Hongping ( October 2020 , Crystal Growth & Design)

   null (Ed.)
4. Band offsets of (100) β -(Al x Ga 1−x ) 2 O 3 / β -Ga 2 O 3 heterointerfaces grown via MOCVD

   https://doi.org/10.1063/5.0031584  

   Bhuiyan, A F ; Feng, Zixuan ; Johnson, Jared M. ; Huang, Hsien-Lien ; Hwang, Jinwoo ; Zhao, Hongping ( December 2020 , Applied Physics Letters)

   null (Ed.)
5. Thermal Conductivity of β-Phase Ga 2 O 3 and (Al x Ga 1– x ) 2 O 3 Heteroepitaxial Thin Films

   https://doi.org/10.1021/acsami.1c08506  

   Song, Yiwen ; Ranga, Praneeth ; Zhang, Yingying ; Feng, Zixuan ; Huang, Hsien-Lien ; Santia, Marco D. ; Badescu, Stefan C. ; Gonzalez-Valle, C. Ulises ; Perez, Carlos ; Ferri, Kevin ; et al ( August 2021 , ACS Applied Materials & Interfaces)