![]() Several growth techniques have recently been studied for the preparation of large-area GaN films but a major obstacle is still represented by the lack of a suitable material that could be used as a substrate for the nitrides while being compatible from both thermal and structural points of view. ![]() In addition, the DBS measurements upheld the aforementioned results with a higher effective positron diffusion length L eff GaN 2 = 75 ± 20 nm for the GaN layer. This reveals an improved crystal quality of the GaN with SiC as a growth template. Compared with previously investigated heterostructures (on Si and Al 2O 3 substrates), the obtained dislocation correlation lengths ( L e = 171 nm and L s =288 nm) and the mean distance between two dislocations ( r d = 82 nm) are higher. ![]() Within the epitaxial GaN layer defined by the relationship F 4 ¯ 3 m (111) 3C-SiC || P 63 m c (0002) AlN || P 63 m c (0002) GaN, the total dislocation density has been assessed as being 1.47 × 10 10 cm −2. Moreover, a comparative analysis with our previous work (i.e., GaN/AlN/Si and GaN/AlN/Al 2O 3) has been carried out. In addition, the dislocation densities together with the defect correlation lengths are investigated via High-Resolution X-ray Diffraction (HR-XRD) and the characteristic positron diffusion length is achieved by Doppler Broadening Spectroscopy (DBS). Several aspects such as the growth relation between the layers of the GaN/AlN/SiC heterostructure, the consistency of the interfaces, and elemental diffusion are achieved by High Resolution Transmission Electron Microscopy (HR-TEM).
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