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1. A review of band structure and material properties of transparent conducting and semiconducting oxides: Ga ₂ O ₃ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , CdO, NiO, CuO, and Sc ₂ O ₃

   https://doi.org/10.1063/5.0078037  

   Spencer, Joseph A.; Mock, Alyssa L.; Jacobs, Alan G.; Schubert, Mathias; Zhang, Yuhao; Tadjer, Marko J. (March 2022, Applied Physics Reviews)

   This Review highlights basic and transition metal conducting and semiconducting oxides. We discuss their material and electronic properties with an emphasis on the crystal, electronic, and band structures. The goal of this Review is to present a current compilation of material properties and to summarize possible uses and advantages in device applications. We discuss Ga 2 O 3 , Al 2 O 3 , In 2 O 3 , SnO 2 , ZnO, CdO, NiO, CuO, and Sc 2 O 3 . We outline the crystal structure of the oxides, and we present lattice parameters of the stable phases and a discussion of the metastable polymorphs. We highlight electrical properties such as bandgap energy, carrier mobility, effective carrier masses, dielectric constants, and electrical breakdown field. Based on literature availability, we review the temperature dependence of properties such as bandgap energy and carrier mobility among the oxides. Infrared and Raman modes are presented and discussed for each oxide providing insight into the phonon properties. The phonon properties also provide an explanation as to why some of the oxide parameters experience limitations due to phonon scattering such as carrier mobility. Thermal properties of interest include the coefficient of thermal expansion, Debye temperature, thermal diffusivity, specific heat, and thermal conductivity. Anisotropy is evident in the non-cubic oxides, and its impact on bandgap energy, carrier mobility, thermal conductivity, coefficient of thermal expansion, phonon modes, and carrier effective mass is discussed. Alloys, such as AlGaO, InGaO, (Al x In y Ga 1− x− y ) 2 O 3 , ZnGa 2 O 4 , ITO, and ScGaO, were included where relevant as they have the potential to allow for the improvement and alteration of certain properties. This Review provides a fundamental material perspective on the application space of semiconducting oxide-based devices in a variety of electronic and optoelectronic applications. 

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2. MOCVD Growth of β-Ga ₂ O ₃ on (001) Ga ₂ O ₃ Substrates

   https://doi.org/10.1021/acs.cgd.4c00060  

   Meng, Lingyu; Yu, Dongsu; Huang, Hsien-Lien; Chae, Chris; Hwang, Jinwoo; Zhao, Hongping (May 2024, Crystal Growth & Design)
3. Crystal Chemistry and Phonon Heat Capacity in Quaternary Honeycomb Delafossites: Cu[Li _1/3 Sn _2/3 ]O ₂ and Cu[Na _1/3 Sn _2/3 ]O ₂

   https://doi.org/10.1021/acs.inorgchem.8b01866  

   Abramchuk, Mykola; Lebedev, Oleg I.; Hellman, Olle; Bahrami, Faranak; Mordvinova, Natalia E.; Krizan, Jason W.; Metz, Kenneth R.; Broido, David; Tafti, Fazel (October 2018, Inorganic Chemistry)
4. Thermal Stability of Transparent ITO/n-Ga ₂ O ₃ /n+-Ga ₂ O ₃ /ITO Rectifiers

   https://doi.org/10.1149/2162-8777/ac3ace  

   Xia, Xinyi; Xian, Minghan; Ren, Fan; Rasel, Md Abu; Haque, Aman; Pearton, S. J. (November 2021, ECS Journal of Solid State Science and Technology)

   The thermal stability of n/n + β -Ga 2 O 3 epitaxial layer/substrate structures with sputtered ITO on both sides to act as rectifying contacts on the lightly doped layer and Ohmic on the heavily doped substrate is reported. The resistivity of the ITO deposited separately on Si decreased from 1.83 × 10 −3 Ω.cm as-deposited to 3.6 × 10 −4 Ω.cm after 300 °C anneal, with only minor reductions at higher temperatures (2.8 × 10 −4 Ω.cm after 600 °C anneals). The Schottky barrier height also decreased with annealing, from 0.98 eV in the as-deposited samples to 0.85 eV after 500 °C annealing. The reverse breakdown voltage exhibited a negative temperature coefficient of −0.46 V.C −1 up to an annealing temperature of 400 °C and degraded faster at higher temperatures. Transmission Electron Microscopy showed significant reaction at the ITO and Ga 2 O 3 interface above 300 °C, with a very degraded contact stack after annealing at 500 °C. 

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5. Tandem In ₂ O ₃ -Pt/Al ₂ O ₃ catalyst for coupling of propane dehydrogenation to selective H ₂ combustion

   https://doi.org/10.1126/science.abd4441  

   Yan, Huan; He, Kun; Samek, Izabela A.; Jing, Dian; Nanda, Macy G.; Stair, Peter C.; Notestein, Justin M. (March 2021, Science)

   Tandem catalysis couples multiple reactions and promises to improve chemical processing, but precise spatiotemporal control over reactive intermediates remains elusive. We used atomic layer deposition to grow In₂O₃over Pt/Al₂O₃, and this nanostructure kinetically couples the domains through surface hydrogen atom transfer, resulting in propane dehydrogenation (PDH) to propylene by platinum, then selective hydrogen combustion by In₂O₃, without excessive hydrocarbon combustion. Other nanostructures, including platinum on In₂O₃or platinum mixed with In₂O₃, favor propane combustion because they cannot organize the reactions sequentially. The net effect is rapid and stable oxidative dehydrogenation of propane at high per-pass yields exceeding the PDH equilibrium. Tandem catalysis using this nanoscale overcoating geometry is validated as an opportunity for highly selective catalytic performance in a grand challenge reaction. 

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