tailieunhanh - Báo cáo hóa học: " Intense Red Catho- and Photoluminescence from 200 nm Thick Samarium Doped Amorphous AlN Thin Films"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: ntense Red Catho- and Photoluminescence from 200 nm Thick Samarium Doped Amorphous AlN Thin Films | Nanoscale Res Lett 2009 4 748-752 DOI S11671-009-9309-7 NANO EXPRESS Intense Red Catho- and Photoluminescence from 200 nm Thick Samarium Doped Amorphous AlN Thin Films Muhammad Maqbool Tariq Ali Received 21 January 2009 Accepted 2 April 2009 Published online 25 April 2009 to the authors 2009 Abstract Samarium Sm doped aluminum nitride AlN thin films are deposited on silicon 100 substrates at 77 K by rf magnetron sputtering method. Thick films of 200 nm are grown at 100-200 watts RF power and 5-8 m Torr nitrogen using a metal target of Al with Sm. X-ray diffraction results show that films are amorphous. Cathodoluminescence CL studies are performed and four peaks are observed in Sm at 564 600 648 and 707 nm as a result of 4G5 2 6H5 2 4G5 2 6H7 2 4G5 2 6H9 2 and 4G5 2 6H11 2 transitions. Photoluminescence PL provides dominant peaks at 600 and 707 nm while CL gives the intense peaks at 600 nm and 648 nm respectively. Films are thermally activated at 1 200 K for half an hour in a nitrogen atmosphere. Thermal activation enhances the intensity of luminescence. Keywords Cathodoluminescence Photoluminescence Thermal activation XRD Samarium AlN Introduction Rear-earth doped nitride semiconductors thin films are attracting increasing attention as phosphor materials and are used for optical displays 1-5 . Sputter deposited AlN has been shown to be a viable host for luminescent rare earth RE ions due to its transparency over a wide range M. Maqbool El Department of Physics and Astronomy Ball State University Muncie IN 47306 USA e-mail mmaqbool@ T. Ali Department of Physics State University of New York at Buffalo Buffalo NY 14260 USA including the UV IR and entire visible range 6-17 . Recent progress toward nitride-based light-emitting diode and electroluminescent devices ELDs has been made using crystalline and amorphous AlN doped with a variety of rare-earth elements 1-9 . The electronic structure of the RE ions differ from the other elements and are .