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Structural characterization of cubic GaN films using transmission electron microscopy |
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| รหัสดีโอไอ | |
| Title | Structural characterization of cubic GaN films using transmission electron microscopy |
| Creator | Surang Sumnavadee |
| Contributor | Sakuntam Sanorpim, Boonchoat Paosawatyanyong |
| Publisher | Chulalongkorn University |
| Publication Year | 2553 |
| Keyword | Cubic GaN films, Transmission electron microscopy, ฟิล์มคิวบิกแกลเลียมไนไตรด์, จุลทรรศน์อิเล็กตรอนแบบทรานสมิชชัน |
| Abstract | Cubic GaN (c-GaN) films grown by metalorganic vapor phase epitaxy were investigated using transmission electron microscopy (TEM) to verify effects of growth conditions on the film quality. The c-GaN films used in this study were grown on GaAs (001) and (311) oriented substrates with different growth temperatures of the GaN buffer layers (550-600℃). It is found that all the c-GaN grown films have a cubic structure as a main crystal structure. However, for higher growth temperature, hexagonal phase inclusions found to easily construct along the {111} facets of c-GaN associated with the formation of stacking faults (SFs) starting from the (111) step on the GaAs (001) grown surface. To reduce a generation of hexagonal phase in c-GaN films, growth temperature of a GaN buffer layer is optimized and affected on the formation of SFs in the c-GaN films. The best quality of c-GaN films grown on GaAs (001) substrates with cubic phase purity was achieved by the growth with the optimum growth temperature of GaN films of 900°C and low buffer growth temperature of 575℃. Besides, the c-GaN film on GaAs (311) substrate with identical growth conditions results in the presence of SFs but the hexagonal single crystal is invisible. These results demonstrate that c-GaN on GaAs (311) exhibits a better film quality with lower density of SFs compared to that in c-GaN on GaAs (001). This might be due to a difficulty of a generation of the (111) step on the GaAs (311) grown surface. |
| URL Website | cuir.car.chula.ac.th |
