The influence of erbium doping of Al–N sputtered coatings on their optical properties

• Published in: Thin solid films Vol. 446; no. 2; pp. 264 - 270
• Main Authors: Oliveira, J.C, Cavaleiro, A, Vieira, M.T, Bigot, L, Garapon, C, Mugnier, J, Jacquier, B
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.01.2004; Elsevier Science
• Subjects: Aluminium nitride; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Exact sciences and technology; Iii-v semiconductors; Lanthanides; Luminescence; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photoluminescence; Physics; Sputtering; Lanthanides; Sputtering; Aluminium nitride; Luminescence; Scanning electron microscopy; Annealing; Inorganic compounds; Refractive index; Crystallization; Doping; Photoluminescence; Binary compounds; XRD; Experimental study; Thin films; Magnetrons; Aluminium nitrides; Chemical composition; Reactive sputtering; Erbium additions; III-V semiconductors
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2003.09.055

Room-temperature photoluminescence (PL) measurements were performed on erbium-doped AlN thin films deposited by r.f. reactive magnetron sputtering on steel and amorphous quartz substrates. The Al/(N+Al) ratio in the as-deposited films varies in the range from 0.48 to 0.51, while erbium content ranges from 0.2 to 3.5 at.%. X-ray diffraction showed that the AlN(Er) films with erbium contents up to 1.4 at.% have the hexagonal AlN crystalline structure and a preferential orientation following the [0 0 1] direction. However, as a consequence of lattice distortion and/or defect generation originated by the incorporation of erbium atoms in the AlN structure, the films became amorphous for higher erbium contents. All the as-deposited films exhibited room-temperature PL at 1.54 μm, indicating that at least part of the erbium species are optically active in the as-grown samples. Subsequent annealing of the films led to an intensification of the PL signal up to a factor of 6 for the films heat-treated at 1075 K. Within the range of chemical compositions studied in this work, the PL signal increased with increasing erbium content. A weak green visible PL was also detected for the samples doped with the highest erbium contents when annealed at high temperatures.