Investigation on Surface Polarization of Al2O3-capped GaN/AlGaN/GaN Heterostructure by Angle-Resolved X-ray Photoelectron Spectroscopy
| Autor: | Kai Cheng, Ning Wang, Ji Sheng Pan, Hongyu Yu, Tian Li Duan |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Annealing (metallurgy) Nanochemistry ARXPS Gallium nitride Nanotechnology 02 engineering and technology 01 natural sciences Atomic layer deposition chemistry.chemical_compound X-ray photoelectron spectroscopy 0103 physical sciences lcsh:TA401-492 General Materials Science Electronic band structure 010302 applied physics Nano Express business.industry Heterojunction 021001 nanoscience & nanotechnology Condensed Matter Physics Polarization (waves) chemistry Surface polarization Interfacial layer Optoelectronics lcsh:Materials of engineering and construction. Mechanics of materials GaN heterostructure 0210 nano-technology business |
| Zdroj: | Nanoscale Research Letters Nanoscale Research Letters, Vol 12, Iss 1, Pp 1-6 (2017) |
| ISSN: | 1556-276X 1931-7573 |
| DOI: | 10.1186/s11671-017-2271-x |
| Popis: | The surface polarization of Ga-face gallium nitride (GaN) (2 nm)/AlGaN (22 nm)/GaN channel (150 nm)/buffer/Si with Al2O3 capping layer is investigated by angle-resolved X-ray photoelectron spectroscopy (ARXPS). It is found that the energy band varies from upward bending to downward bending in the interface region, which is believed to be corresponding to the polarization variation. An interfacial layer is formed between top GaN and Al2O3 due to the occurrence of Ga–N bond break and Ga–O bond forming during Al2O3 deposition via the atomic layer deposition (ALD). This interfacial layer is believed to eliminate the GaN polarization, thus reducing the polarization-induced negative charges. Furthermore, this interfacial layer plays a key role for the introduction of the positive charges which lead the energy band downward. Finally, a N2 annealing at 400 °C is observed to enhance the interfacial layer growth thus increasing the density of positive charges. |
| Databáze: | OpenAIRE |
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