Photoelectron spectroscopic study of iodine- and bromine-treated indium tin oxides and their interfaces with organic films

• Published in: Chemical physics letters Vol. 370; no. 3; pp. 425 - 430
• Main Authors: Sun, X.H., Cheng, L.F., Liu, M.W., Liao, L.S., Wong, N.B., Lee, C.S., Lee, S.T.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 14.03.2003; Elsevier Science
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron and ion emission by liquids and solids; impact phenomena; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Interfaces, heterostructures, nanostructures; Photoemission and photoelectron spectra; Physics; Surface double layers, schottky barriers, and work functions; Tin oxides; Photoelectron spectra; Work functions; Frontier orbital; Ternary compounds; Electroluminescent devices; Gas solid interface; Surface treatments; Indium oxides; Experimental study; Charge carrier injection
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/S0009-2614(03)00135-0

Work function variations of indium tin oxide (ITO) treated with solutions of iodine and bromine as well as bromine vapor were studied by ultraviolet and X-ray photoelectron spectroscopies. Interfaces between the treated ITO and NPB were also investigated. Treatments by iodine and bromine solutions, and bromine vapor led to work function increase by as much as 0.6, 0.7, and 0.9 eV, respectively. After the halogen treatments, the hole-injection barrier for the NPB/ITO contact was remarkably decreased. A light-emitting device fabricated with bromine vapor-treated ITO as anode clearly demonstrated better hole injection at the ITO/NPB interface and a lower drive voltage.