Raman mapping, photoluminescence investigations, and finite element analysis of epitaxial lateral overgrown GaN on silicon substrates

Epitaxial lateral overgrown (ELO) GaN grown by metalorganic vapor phase epitaxy on Si substrates was characterized using Raman mapping, photoluminescence (PL) experiments and finite element (FE) analysis. Stress in the structures was determined from the E2 phonon frequency and compared to FE results. Low temperature PL spectra are dominated by donor bound exciton (DBE) emission at (3.457–3.459) eV. PL spectra reveal a peak at ∼3.404 eV in window regions attributed to structural defects in the GaN. Differences in crystalline quality between window and overgrown regions of ELO GaN were investigated.