Article
Materials Science, Multidisciplinary
Tuo Sheng, Xing-Zhao Liu, Ling-Xuan Qian, Bo Xu, Yi-Yu Zhang
Summary: Metal-semiconductor-metal solar-blind ultraviolet photoconductors based on beta-Ga2O3 thin films were fabricated and the effects of annealing on their characteristics and photoconductivity were studied. Higher annealing temperature resulted in lower crystalline quality and device photoresponsivity. The vacuum-annealed sample showed the highest photoresponsivity and the oxygen-annealed sample effectively suppressed persistent photoconductivity.
Article
Chemistry, Multidisciplinary
Babak Nikoobakht, Aaron C. Johnston-Peck, David Laleyan, Ping Wang, Zetian Mi
Summary: A novel approach was presented for growth of surface-directed spinel ZnGa2O4 and beta-Ga2O3 nanofins coated with a non-polar GaN shell, utilizing a vacancy-assisted mechanism for exchange between Zn and Ga. The predictability over surface registries and tunable porosity of the core/shell fins is anticipated to be significant for various applications.
Article
Nanoscience & Nanotechnology
Kenny Huynh, Michael E. Liao, Akhil Mauze, Takeki Itoh, Xingxu Yan, James S. Speck, Xiaoqing Pan, Mark S. Goorsky
Summary: The orientational dependence of interfacial reaction between aluminum and different β-Ga2O3 substrates (010, (001), and ((2) over bar 01)) was investigated. It was found that the orientation of β-Ga2O3 substrates influences the formation of aluminum oxide layers and diffusional pathways.
Article
Multidisciplinary Sciences
Janusz Sadowski, Anna Kaleta, Serhii Kryvyi, Dorota Janaszko, Boguslawa Kurowska, Marta Bilska, Tomasz Wojciechowski, Jaroslaw Z. Domagala, Ana M. Sanchez, Slawomir Kret
Summary: The incorporation of Bi into GaAs-(Ga,Al)As-Ga(As,Bi) core-shell nanowires grown by molecular beam epitaxy is studied. Bi-doped shells are smooth at low Bi fluxes, while higher Bi fluxes lead to Bi droplet segregation on the nanowire sidewalls, acting as catalysts for the growth of branches.
SCIENTIFIC REPORTS
(2022)
Article
Nanoscience & Nanotechnology
Patrick Vogt, Felix V. E. Hensling, Kathy Azizie, Celesta S. Chang, David Turner, Jisung Park, Jonathan P. McCandless, Hanjong Paik, Brandon J. Bocklund, Georg Hoffman, Oliver Bierwagen, Debdeep Jena, Huili G. Xing, Shin Mou, David A. Muller, Shun-Li Shang, Zi-Kui Liu, Darrell G. Schlom
Summary: Introduces a growth method called suboxide molecular-beam epitaxy (S-MBE) that significantly enhances the growth rates of Ga2O3 and related materials while maintaining excellent crystalline quality, applicable to a wide range of oxide materials.
Article
Physics, Applied
Mengen Wang, Sai Mu, Chris G. Van de Walle
Summary: Studies suggest that silicon and tin can replace gallium sites in Ga2O3 and prefer different structural sites. Under surface reconstructions, silicon and tin may also occupy thermodynamically less preferred sites.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
D. P. Wilson, V. G. Dubrovskii, R. R. LaPierre
Summary: GaAs nanowire arrays were grown by molecular beam epitaxy using the self-assisted vapor-liquid-solid method with Ga droplets as seed particles. The diameter of the nanowires was determined by vapor-solid growth on the sidewalls, rather than Ga pre-deposition. The maximum nanowire yield was achieved when the Ga droplet volume approximately equaled the hole volume.
Article
Chemistry, Physical
Yuki K. Wakabayashi, Takuma Otsuka, Yoshiharu Krockenberger, Hiroshi Sawada, Yoshitaka Taniyasu, Hideki Yamamoto
Summary: The lack of an appropriate way to handle missing data has been a crucial problem in achieving innovative high-throughput materials growth with machine learning and automation techniques. In this study, a Bayesian optimization algorithm is proposed to complement the missing data in optimizing materials growth parameters. The algorithm provides a flexible optimization approach that searches a wide multi-dimensional parameter space. The effectiveness of the method is demonstrated through simulated data and its implementation in the growth of SrRuO3 using machine-learning-assisted molecular beam epitaxy, achieving high-quality films in just 35 growth runs.
NPJ COMPUTATIONAL MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Dmitry V. Averyanov, Ivan S. Sokolov, Igor A. Karateev, Alexander N. Taldenkov, Oleg A. Kondratev, Oleg E. Parfenov, Andrey M. Tokmachev, Vyacheslav G. Storchak
Summary: This study focuses on the integration of oxides with silicon, particularly emphasizing the direct EuO/Si contact. An alternative route, different from traditional methods, was successfully used to address the issue of atomically sharp interfaces in single-crystalline epitaxial films. The results not only represent tangible progress in manufacturing EuO/Si contacts, but also provide a general framework for the monolithic integration of functional oxides with semiconductors.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Review
Chemistry, Multidisciplinary
Abdul Kareem K. Soopy, Zhaonan Li, Tianyi Tang, Jiaqian Sun, Bo Xu, Chao Zhao, Adel Najar
Summary: The review summarizes recent advancements in nitride nanostructures and their applications, including synthesis, growth, and application of nitride materials. The discussion focuses on the growth of nitride materials on various substrates and the recent development of In(Ga)N nanostructure applications. The review also addresses the challenges and future directions in the field.
Article
Materials Science, Multidisciplinary
Peiyao Xiao, Xu Zhang, Xianglin Peng, Lu Qiao, Ji Li, Chang Wang, Shuyu Liu, Yuxiang Liu, Zhitao Wu, Wende Xiao
Summary: Nanostructured NbSe2 is of great interest due to its exotic properties and potential applications. However, it remains a challenge to prepare NbSe2 nanostructures with high edge-to-surface ratio, which is highly desirable for catalysis applications. In this study, we demonstrate the controllable growth of 2D NbSe2 with irregular geometries on highly oriented pyrolytic graphite substrates by tuning the balance between growth and ion etching. Characterization using various techniques confirms the morphology and composition of the as-grown NbSe2 flakes. Our work highlights the important role of ion etching and provides a pathway for growing 2D materials with different geometries.
Article
Chemistry, Multidisciplinary
Emmanuel Chereau, Vladimir G. Dubrovskii, Gabin Gregoire, Geoffrey Avit, Philipp Staudinger, Heinz Schmid, Catherine Bougerol, Pierre-Marie Coulon, Philip A. Shields, Agnes Trassoudaine, Evelyne Gil, Ray R. LaPierre, Yamina Andre
Summary: The selective area growth (SAG) of GaAs nanowires (NWs) by catalyst-free vapor-solid mechanism was achieved. Well-ordered GaAs NWs in perfect hexagonal shape were grown on GaAs (111)B substrates patterned with a dielectric mask using hydride vapor phase epitaxy (HVPE). The study investigated the impact of growth conditions and hole size on NW lengths and growth rates. High aspect ratio NWs were obtained by reducing As-4 partial pressure and decreasing the hole size, indicating the contribution of surface diffusion of Ga adatoms to axial growth rate.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Materials Science, Coatings & Films
Fedor Hrubisak, Kristina Husekova, Xiang Zheng, Alica Rosova, Edmund Dobrocka, Milan Tapajna, Matej Micusik, Peter Nadazdy, Fridrich Egyenes, Javad Keshtkar, Eva Kovacova, James W. Pomeroy, Martin Kuball, Filip Gucmann
Summary: In this study, monoclinic ss-Ga2O3 and orthorhombic kappa-Ga2O3 thin films were grown on highly thermally conductive 4H-SiC substrates using liquid-injection metal-organic chemical vapor deposition. Both gallium precursors produced the ss phase, but only the latter led to growth of kappa-Ga2O3. The best growth conditions for ss-Ga2O3 were a temperature of 700 degrees C and O-2 flows in the range of 600-800 SCCM. For kappa-Ga2O3, a narrow growth window was observed, with the best results at a temperature of 600 degrees C and an O-2 flow of 800 SCCM. The results suggest the potential of integrating Ga2O3 and SiC for improved thermal management and reliability of future high power Ga2O3-based devices.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Engineering, Electrical & Electronic
Yue Kuang, Xuanhu Chen, Tongchuan Ma, Qianqian Du, Yanfang Zhang, Jinggang Hao, Fang-Fang Ren, Bin Liu, Shunming Zhu, Shulin Gu, Rong Zhang, Youdou Zheng, Jiandong Ye
Summary: This study successfully constructed the heterostructure of single crystalline metastable orthorhombic kappa-Ga2O3 epilayers and cubic In2O3 (111) using laser molecular beam epitaxy. Analysis of XPS and Hall results revealed the formation of a two-dimensional electron gas at the heterostructure interface with high carrier concentration and mobility.
ACS APPLIED ELECTRONIC MATERIALS
(2021)
Article
Chemistry, Physical
Alexandria R. C. Bredar, Miles D. Blanchet, Andricus R. Burton, Bethany E. Matthews, Steven R. Spurgeon, Ryan B. Comes, Byron H. Farnum
Summary: Nanocrystalline MnFe2O4 and Fe3O4 thin-films were studied as electrocatalysts for the oxygen reduction reaction (ORR) in alkaline solutions. The results showed that, unlike nanocrystalline MnFe2O4, the diffusion-limited current for oxygen reduction was achieved at Fe redox features due to the low density of Mn surface termination and the poor conductivity of the MnFe2O4 film. This study revealed the influence of lattice mismatch on the growth and surface properties of thin-film catalysts and posed challenges for ORR catalysis research.
