Oxygen flux influence on the morphological, structural and optical properties of Zn1-xMgxO thin films grown by plasma-assisted molecular beam epitaxy

• Published in: Applied surface science Vol. 254; no. 15; pp. 4886 - 4890
• Main Authors: SU, S. C, LU, Y. M, ZHANG, Z. Z, LI, B. H, SHEN, D. Z, YAO, B, ZHANG, J. Y, ZHAO, D. X, FAN, X. W
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Science 30.05.2008
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Molecular, atomic, ion, and chemical beam epitaxy; Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity); Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Physics; Single-crystal and powder diffraction; Structure and morphology; thickness; Structure of solids and liquids; crystallography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; X-ray diffraction and scattering; Scanning electron microscopy; Oxygen; Inorganic compounds; Photoluminescence; Roughness; Field emission; XRD; Nanostructures; Fabrication property relation; Transmittance; Film growth; Surface structure; P-MBE; Thin films; Energy gap; Zn1-xMgxO; Zn/Mg; Molecular beam epitaxy
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2008.01.132

The Zn1-xMgxO thin films were grown on Al2O3 substrate with various O2 flow rates by plasma-assisted molecular beam epitaxy (P-MBE). The growth conditions were optimized by the characterizations of morphology, structural and optical properties. The Mg content of the Zn1-xMgxO thin film increases monotonously with decreasing the oxygen flux. X-ray diffractometer (XRD) measurements show that all the thin films are preferred (0 0 2) orientated. By transmittance and absorption measurements, it was found that the band gap of the film decreases gradually with increasing oxygen flow rate. The surface morphology dependent on the oxygen flow rate was also studied by field emission scanning electron microscopy (FE-SEM). The surface roughness became significant with increasing oxygen flow rate, and the nanostructures were formed at the larger flow rate. The relationship between the morphology and the oxygen flow rate of Zn1-xMgxO films was discussed.