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Nanostructural analysis of cubic GaN and cubic InN films by transmission electron microscopy |
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| รหัสดีโอไอ | |
| Title | Nanostructural analysis of cubic GaN and cubic InN films by transmission electron microscopy |
| Creator | Jamreonta Parinyataramas |
| Contributor | Sakuntam Sanorpim, Chanchana Thanachayanont |
| Publisher | Chulalongkorn University |
| Publication Year | 2554 |
| Keyword | Nanostructures, Transmission electron microscopy, โครงสร้างนาโน, จุลทรรศน์อิเล็กตรอนแบบทรานสมิชชัน |
| Abstract | Structural analysis of the cubic-phase GaN (c-GaN) and InN (c-InN) thin films was performed in nano-scale using transmission electron microscopy (TEM) to verify the structural-phase transformation and the structural defect formation, which may be affected by the structural similarities between the cubic (111) and hexagonal (0001) planes with rotating 60. This study found out that the insertion of buffer layer is a successful method to protect the (001) GaAs substrate from thermal decomposition, which introduces the (111) stepped on (001) GaAs surface. This results in a structural-phase transformation from cubic to mixed cubic/hexagonal-phases in the cubic nitride films. Moreover, an anisotropic (111) steps along the [110] and [110] direction of the buffer layer induced anisotropic distribution of defects observed in cross-sectional TEM images taken along the [110] and [110] zone axes. Zone axis dependent type of defects is due to a different atomic structure of surface step on the (001) AlGaAs buffer layer. Cross-sectional TEM images taken along [110] zone axis show a less stacking faults (SFs) but appear a cubic twin with an epitaxial orientation of [114]cubic twin//[110]substrate. Only some treading dislocations were observed on top region of the layer. A present of cubic twin also induced an anti-phase domain boundary in the layer. For the c-InN thin films on MgO (001) substrate with a c-GaN buffer, the In-rich growth condition was found to improve the crystal quality of the c-InN grown layer. Hexagonal phase generation decreased with increasing growth temperature and In flux. However, the structural-phase transformation from cubic to mixed cubic/hexagonal phases in the best quality c-InN films exhibited in a form of planar defects, such as stacking faults and twins generated from the interface between the c-GaN buffer layer and the c-InN film. |
| URL Website | cuir.car.chula.ac.th |
