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β-phase gallium oxide (Ga2O3) is an emerging ultrawide bandgap (UWBG) semiconductor with a bandgap energy of ∼ 4.8 eV and a predicted high critical electric field strength of ∼8 MV/cm, enabling promising applications in next generation high power electronics and deep ultraviolet optoelectronics. The advantages of Ga2O3 also stem from its availability of single crystal bulk native substrates synthesized from melt, and its well-controllable n-type doping from both bulk growth and thin film epitaxy. Among several thin film growth methods, metalorganic chemical vapor deposition (MOCVD) has been demonstrated as an enabling technology for developing high-quality epitaxy of Ga2O3 thin films, (AlxGa1−x)2O3 alloys, and heterostructures along various crystal orientations and with different phases. This tutorial summarizes the recent progresses in the epitaxial growth of β-Ga2O3 thin films via different growth methods, with a focus on the growth of Ga2O3 and its compositional alloys by MOCVD. The challenges for the epitaxial development of β-Ga2O3 are discussed, along with the opportunities of future works to enhance the state-of-the-art device performance based on this emerging UWBG semiconductor material system.
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This content will become publicly available on April 1, 2026
Orientation reconstruction of transformation α titanium alloys via polarized light microscopy: Methodology and assessment
Emerging microstructural characterization methods have received increased attention owing to their promise of relatively inexpensive and rapid measurement of polycrystalline surface morphology and crystallographic orientations. Among these nascent methods, polarized light microscopy (PLM) is attractive for characterizing alloys comprised of hexagonal crystals, but is hindered by its inability to measure complete crystal orientations. In this study, we explore the potential to reconstruct quasi-deterministic orientations for titanium microstructures characterized via PLM by considering the Burgers orientation relationship between the room temperature α (HCP) phase fibers measured via PLM, and the β (BCC) phase orientations of the parent grains present above the transus temperature. We describe this method—which is capable of narrowing down the orientations to one of four possibilities—and demonstrate its abilities on idealized computational samples in which the parent β microstructure is fully, unambiguously known. We further utilize this method to inform the instantiation of samples for crystal plasticity simulations, and demonstrate the significant improvement in deformation field predictions when utilizing this reconstruction method compared to using results from traditional PLM.
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- Award ID(s):
- 2143808
- PAR ID:
- 10595798
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- Materials Characterization
- Volume:
- 222
- Issue:
- C
- ISSN:
- 1044-5803
- Page Range / eLocation ID:
- 114841
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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