Fabrication and characterization of high quality undoped and Ga2O3-doped ZnO thin films by reactive electron beam co-evaporation technique

• Published in: Journal of crystal growth Vol. 275; no. 3-4; pp. 512 - 520
• Main Authors: AL ASMAR, R, JUILLAGUET, S, RAMONDA, M, GIANI, A, COMBETTE, P, KHOURY, A, FOUCARAN, A
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 01-03-2005
• Subjects: Condensed Matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electronics; Engineering Sciences; Exact sciences and technology; Ii-vi semiconductors; 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; Vapor phase epitaxy; growth from vapor phase; Chemisorption; Atomic force microscopy; Al. Atomic force microscopy; Inorganic compounds; Vacancies; Transition element compounds; Doping; Interstitials; Photoluminescence; Binary compounds; Crystal growth from vapors; XRD; Experimental study; Al. Hall measurements; Al. Photoluminescence measurements; B1. Ga2O3-doped ZnO; Thin films; Zinc oxides; Quantity ratio; II-VI semiconductors; A3. E-beam co-evaporation; Carrier density; Electron beam evaporation; Deep level; ROOM-TEMPERATURE; E-beam co-evaporation; DEPOSITION; OPTICAL-PROPERTIES; Ga2O3-doped ZnO; photoluminescence measurements; atomic force microscopy; hall measurements; EVAPORATION; EPITAXY; PHOTOLUMINESCENCE PROPERTIES; LUMINESCENCE; GROWTH; ZINC-OXIDE FILMS; LAYER
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2004.12.034

High-quality undoped and Ga2O3-doped ZnO thin films have been co-evaporated by reactive electron beam evaporation in an oxygen environment. The effect of the dopant on the structural, optical and electrical properties has been investigated. X-ray diffraction measurements have shown that the Ga2O3-doped ZnO films are c-axis-oriented and that the linewidth of the (002) peak is sensitive to the variation of the dopant concentration. The 28% Ga2O3-doped ZnO films showed the best crystallinity. The AFM images have shown that the surfaces of the Ga2O3-doped ZnO became smoother by raising the concentration of Ga2O3 in the fabricated films. Photoluminescence on 28% Ga2O3-doped ZnO reveals an enhancement of the near band edge ultraviolet emission at 380nm while the intensity of the deep level emissions weakens. A reduction of the oxygen vacancies as well as the reduction of the zinc interstitials with gallium may explain this effect. Thus the possibility of transitions of electron in the conduction band to a deep acceptor level due to zinc interstitials may decrease. The optical band-gap energy increased with the rise of the dopant concentration. The electrical resistivity increased with the rising of the Ga2O3 concentration while the carrier concentration decreased which is due to chemisorptions of oxygen into the ZnO thin films.