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Ultrawide bandgap β-(AlxGa1−x)2O3 vertical Schottky barrier diodes on (010) β-Ga2O3 substrates are demonstrated. The β-(AlxGa1−x)2O3 epilayer has an Al composition of 21% and a nominal Si doping of 2 × 1017 cm−3 grown by molecular beam epitaxy. Pt/Ti/Au has been employed as the top Schottky contact, whereas Ti/Au has been utilized as the bottom Ohmic contact. The fabricated devices show excellent rectification with a high on/off ratio of ∼109, a turn-on voltage of 1.5 V, and an on-resistance of 3.4 mΩ cm2. Temperature-dependent forward current-voltage characteristics show effective Schottky barrier height varied from 0.91 to 1.18 eV while the ideality factor from 1.8 to 1.1 with increasing temperatures, which is ascribed to the inhomogeneity of the metal/semiconductor interface. The Schottky barrier height was considered a Gaussian distribution of potential, where the extracted mean barrier height and a standard deviation at zero bias were 1.81 and 0.18 eV, respectively. A comprehensive analysis of the device leakage was performed to identify possible leakage mechanisms by studying temperature-dependent reverse current-voltage characteristics. At reverse bias, due to the large Schottky barrier height, the contributions from thermionic emission and thermionic field emission are negligible. By fitting reverse leakage currents at different temperatures, it was identified that Poole–Frenkel emission and trap-assisted tunneling are the main leakage mechanisms at high- and low-temperature regimes, respectively. Electrons can tunnel through the Schottky barrier assisted by traps at low temperatures, while they can escape these traps at high temperatures and be transported under high electric fields. This work can serve as an important reference for the future development of ultrawide bandgap β-(AlxGa1−x)2O3 power electronics, RF electronics, and ultraviolet photonics.
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This content will become publicly available on April 1, 2026
High-Resolution Cr/4H-SiC Schottky Barrier Radiation Detector
This peer-reviewed publication documents the development of Cr/4H-SiC Schottky barrier diodes with high built-in potential (2.2 V), Schottky barrier height (1.14 eV), and exceptional energy resolution (0.5% for 5.486 MeV alpha particles) and compares them with those obtained from devices with conventional metals such as Ni, Mo, and Pd. This work directly corresponds to Tasks 1 and 2 of the project, particularly in exploring alternative metal contacts for enhanced device performance under extreme conditions. It also provides key performance benchmarks for evaluating contact properties that will feed into Task 4, where charge transport behavior is analyzed under irradiation.
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- Award ID(s):
- 2404862
- PAR ID:
- 10613885
- Publisher / Repository:
- IEEE
- Date Published:
- Journal Name:
- IEEE Transactions on Nuclear Science
- Volume:
- 72
- Issue:
- 4
- ISSN:
- 0018-9499
- Page Range / eLocation ID:
- 1644 to 1651
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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