Growth temperature induced effects in non-polar a-plane GaN on r-plane sapphire substrate by RF-MBE

• Published in: Journal of crystal growth 2011, Vol.314 (1), p.5-8
• Main Authors: Rajpalke, Mohana K., Bhat, Thirumaleshwara N., Roul, Basanta, Kumar, Mahesh, Misra, P., Kukreja, L.M., Sinha, Neeraj, Krupanidhi, S.B.
• Format: Article
• Language: English
• Subjects: A1. Atomic force microscopy; A1. High resolution X-ray diffraction; A3. Molecular beam epitaxy; Anisotropy; B1. Nitrides; B2. Non-polar GaN; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Diffraction; Emission; Exact sciences and technology; Gallium nitrides; Materials science; Methods of crystal growth; physics of crystal growth; Methods of deposition of films and coatings; film growth and epitaxy; Micrographs; Molecular beam epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Reflection; Sapphire; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; X-rays
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2010.10.032

Non-polar a-plane GaN films were grown on an r-plane sapphire substrate by plasma assisted molecular beam epitaxy (PAMBE). The effect of growth temperature on structural, morphological and optical properties has been studied. The growth of non-polar a-plane (1 1 −2 0) orientation of the GaN epilayers were confirmed by high resolution X-ray diffraction (HRXRD) study. The X-ray rocking curve (XRC) full width at half maximum of the (1 1 −2 0) reflection shows in-plane anisotropic behavior and found to decrease with increase in growth temperature. The atomic force micrograph (AFM) shows island-like growth for the film grown at a lower temperature. Surface roughness has been decreased with increase in growth temperature. Room temperature photoluminescence shows near band edge emission at 3.434–3.442 eV. The film grown at 800 °C shows emission at 2.2 eV, which is attributed to yellow luminescence along with near band edge emission.