Thesis (M.Sc.)--Chulalongkorn University, 2015

Structural phases of GaN films grown on the GaAs (110) oriented substrates by MOVPE were investigated by μ-Raman spectroscopy with the excitation wavelengths of 473, 514, 532 and 633 nm and XRD. Raman scattering results showed both of cubic and hexagonal phases related phonons. XRD results showed h - GaN (10-13) is the main crystal structure with the c-GaN (110) inclusion in the grown GaN films on GaAs (110). With increasing layer thinness, the results showed GaN film exhibit to cubic structure at the region near to the interface and exhibit to hexagonal structure when the layer thickness increased more than 0.8 µm. The calculation showed only 0.06 % of lattice mismatch between c - GaN (110) and h - GaN (10-13). Thus, the lattice-mismatch significantly involves to construction of the h - GaN (10-13) film on GaAs (110). This investigation showed that a semi-polar GaN (10-13) film was successfully grown on GaAs (110) oriented substrate.