AVS 49th International Symposium
    Applied Surface Science Tuesday Sessions
       Session AS-TuP

Paper AS-TuP8
A New Transparent Conducting Oxide: Indium Molybdenum Oxide (In@sub 2@O@sub 3@ : Mo)

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Topics in Applied Surface Science
Presenter: Y. Yoshida, Colorado School of Mines
Authors: Y. Yoshida, Colorado School of Mines
T.J. Coutts, National Renewable Energy Laboratory
T.A. Gessert, National Renewable Energy Laboratory
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We report our preliminary work on a new transparent conducting oxide, indium molybdenum oxide (IMO, 4% Mo), prepared by radio frequency magnetron sputtering (RF sputtering). Other works have recently reported that thermal reactive evaporated thin films of IMO showed an exceptionally high mobilities of 80 - 130 cm@sup 2@ V@sup -1@ s@sup -1@.@footnote 1@ To study further the functionality of molybdenum in IMO, and to test if the large-area deposition capability afforded by RF sputtering can produce high mobility, we produced In@sub 2@O@sub 3@ (IO) and IMO films in an argon and oxygen atmosphere at a substrate temperature of 350°C. Electrical properties were studied as a function of the ratio of oxygen to argon (O@sub 2@/Ar) from 0 to 1. We found that the best film properties resulted when a small O@sub 2@/Ar ratio was used (@<=@ 0.3). IMO films grown at 0.005 O@sub 2@/Ar achieved a mobility of 37.5 cm@sup 2@ V@sup -1@ s@sup -1@, a carrier concentration of 1.16 x 10@sup 20@ cm@sup -3@, a resistivity of 5 x 10@sup -3@ @ohm@-cm, and ~70% transmission in a visible range (400nm - 900nm). IO film quality was optimized at ~0.025 O@sub 2@/Ar, resulting in a mobility in the range of 20 - 30 cm@sup 2@ V@sup -1@ s@sup -1@, carrier concentration of 2.03 x 10@sup 18@ cm@sup -3@, and resistivity of 9.98 x 10@sup -2@ @ohm@-cm. IMO films showed much better electrical properties than the undoped IO films grown under the same range of conditions. X-ray photoelectron spectroscopy (XPS) confirmed the presence of molybdenum 6+ in the films. X-ray diffraction (XRD) analysis confirmed phase purity in the films and possible texture changes due to variations of the amount of oxygen in the system. @FootnoteText@ @footnote 1@ Y. Meng, X. Yang, H. Chen, J. Shen, Y. Jiang, Z. Zhang, Z. Hua, Thin Solid Films 394 (2001) 219.