Bandgap engineering of α-(AlxGa1-x)2O3 by a mist chemical vapor deposition two-chamber system and verification of Vegard's Law
| Autor: | Yuki Tagashira, Toshiyuki Kawaharamura, Tatsuya Yasuoka, Giang T. Dang, T. Tadokoro, W. Theiss |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Work (thermodynamics) Materials science Physics and Astronomy (miscellaneous) Condensed matter physics Band gap Heterojunction 02 engineering and technology Chemical vapor deposition 021001 nanoscience & nanotechnology 01 natural sciences Lattice constant Vegard's law 0103 physical sciences Direct and indirect band gaps Thin film 0210 nano-technology |
| Zdroj: | Applied Physics Letters. 113:062102 |
| ISSN: | 1077-3118 0003-6951 |
| DOI: | 10.1063/1.5037678 |
| Popis: | This work reports growth of α-(AlxGa1-x)2O3 single crystals with high incorporation of Al by a Mist Chemical Vapor Deposition two-chamber system, which was rationally designed to avoid side-reactions between different precursors during solution preparation for multi-component thin film growth. Multiple acceleration voltages were used in Energy Dispersive X-ray measurements to reliably obtain the Al composition x of the films. As a result, Vegard's law for lattice constants was verified and found to be valid in the α-(AlxGa1-x)2O3 system. However, Vegard's law for optical bandgaps, derived from different models, required an additional term to account for the bowing effect. At x = 0.71, the gaps were 7.74, 7.03, 7.26, and 7.34 eV as derived from the Tauc plots for the direct bandgap, indirect bandgap, Tauc-Lorentz model, and O'Leary-Johnson-Lim model, respectively. The two-chamber system provides reliable and effective control of the Al content in α-(AlxGa1-x)2O3 alloys and heterostructures.This work reports growth of α-(AlxGa1-x)2O3 single crystals with high incorporation of Al by a Mist Chemical Vapor Deposition two-chamber system, which was rationally designed to avoid side-reactions between different precursors during solution preparation for multi-component thin film growth. Multiple acceleration voltages were used in Energy Dispersive X-ray measurements to reliably obtain the Al composition x of the films. As a result, Vegard's law for lattice constants was verified and found to be valid in the α-(AlxGa1-x)2O3 system. However, Vegard's law for optical bandgaps, derived from different models, required an additional term to account for the bowing effect. At x = 0.71, the gaps were 7.74, 7.03, 7.26, and 7.34 eV as derived from the Tauc plots for the direct bandgap, indirect bandgap, Tauc-Lorentz model, and O'Leary-Johnson-Lim model, respectively. The two-chamber system provides reliable and effective control of the Al content in α-(AlxGa1-x)2O3 alloys and heterostructures. |
| Databáze: | OpenAIRE |
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