Near infra-red transparent Mo-doped In2O3 by hetero targets sputtering for phosphorescent organic light emitting diodes

• Published in: Organic electronics Vol. 14; no. 3; pp. 926 - 933
• Main Authors: Shin, Yong-Hee, Kang, Sin-Bi, Lee, Sunghun, Kim, Jang-Joo, Kim, Han-Ki
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.03.2013; Elsevier
• Subjects: Anodes; Applied sciences; Compound structure devices; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Deposition by sputtering; Electronics; Exact sciences and technology; High mobility; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Mo-doped In2O3; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optoelectronic devices; Phosphorescent OLEDs; Photoluminescence; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transmittance; Phosphorescent OLEDs; Mo-doped In2O3; Anodes; Transmittance; High mobility; Transparency; Electrical conductivity; Doping; Molybdenum oxide; Absorption coefficients; O; Rapid thermal annealing; Microelectronic fabrication; Sheet resistivity; Synchrotrons; Impact ionization; Phosphorescence; Carrier mobility; Synchrotron radiation; Organic electronics; Mo-doped In; p i n diodes; Doped materials; MOS structure; Crystallinity; Molybdenum; Preferred orientation; Indium oxide; Near infrared radiation; Tin additions; Organic light emitting diodes; Sputter deposition; Transparent material
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2012.12.036

[Display omitted] ► Hetero-sputtered In–Mo–O anodes for OLEDs were investigated. ► The IMO anode showed a low sheet resistance and high optical transmittance. ► OLEDs with IMO anode showed a comparable performance to OLED with ITO anode. We report a highly near infrared (NIR) transparent MoO3-doped In2O3 (IMO) film prepared by hetero target sputtering for use as a transparent anode in phosphorescent organic light emitting diodes (OLEDs). Effective activation of Mo dopant in the In2O3 matrix and good crystallinity with the (222) preferred orientation from by rapid thermal annealing (RTA) led to the lowest resistivity of 4.25×10−4Ohmcm and sheet resistance of 16.9Ohm/square, comparable to a conventional ITO anode without lose of transparency in the NIR region. Due to high carrier mobility in the IMO matrix, IMO film exhibited higher transmittance in the visible and NIR regions compared to ITO film even though it has a similar resistivity. Both synchrotron X-ray scattering and high resolution transmission electron microscope examinations showed that the optimized IMO film annealed at 600°C had a rectangular shaped columnar structure with a strongly preferred (222) orientation. Identical current density–voltage–luminance and quantum efficiency of the phosphorescent OLED fabricated on an IMO anode were comparable to those of the OLED on a reference ITO anode due to the high transparency and low resistivity of the IMO anode.