High quality (In)GaN films on homoepitaxial substrates

High quality GaN and InGaN epitaxial thin films were deposited by metal organic chemical vapor deposition (MOCVD). Two sets of thin film samples were prepared by varying the substrates and temperatures under a proper condition for achieving better optical properties. The morphological, crystalline quality and optical property of epitaxial layers were characterized by atomic force microscope (AFM), X-ray diffraction (XRD), photoluminescence (PL) and Raman spectra, respectively. It was found that the epitaxial layers grown on GaN homoepitaxial substrate have higher quality than those grown on sapphire substrate. The root mean square (RMS) of GaN film and InGaN film in AFM morphological were 0.5 nm, 2.7 nm respectively. The full width at half maximum (FWHM) of (102) in GaN film on GaN substrate was 33arcsec and the FWHM of (002) in InGaN film on GaN substrate was 50.58arcsec by XRD. The PL peaks of GaN film and InGaN film were 361 nm, 458 nm respectively. The E2 (high) of GaN film and InGaN film in Raman were both 567.08 cm−1.