| Autor: |
Abbas Nasir, Xiong Zhang, Liang Lu, Jin Zhang, Jiadong Lyu, Yiping Cui |
| Jazyk: |
angličtina |
| Rok vydání: |
2021 |
| Předmět: |
|
| Zdroj: |
Materials Research Express, Vol 8, Iss 5, p 055901 (2021) |
| Druh dokumentu: |
article |
| ISSN: |
2053-1591 |
| DOI: |
10.1088/2053-1591/abff0a |
| Popis: |
The non-polar a -AlGaN epitaxial film was successfully grown on the semi-polar r- sapphire substrate by metal-organic chemical vapor deposition technique. An Al-composition-graded Al _x Ga _1−x N (x = 0.0 to 1.0) intermediate layer with varying film thickness from 260 to 695 nm was deposited between the high-temperature AlN layer and the non-polar a- AlGaN epitaxial film to enhance the morphological and crystalline quality. The non-polar a -AlGaN epitaxial films were investigated by using atomic force microscopy (AFM), high-resolution x-ray diffraction, photoluminescence (PL) spectroscopy and the Hall effect measurement techniques. The characterisation results indicate substantial improvements in surface morphology and crystalline quality for the non-polar a- AlGaN epitaxial film grown by adding an Al-composition-graded AlGaN intermediate layer. The surface roughness measured from AFM and the defect-related emission (yellow band) relative to the near-band-edge emission from PL spectra were decreased significantly by optimizing the layer thickness of the Al-composition-graded AlGaN layer. A relatively low background carrier concentration down to −4.4 × ${10}^{17}$ cm ^−3 was achieved from Hall effect measurement for the non-polar a- AlGaN epitaxial film. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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