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Published online by Cambridge University Press: 15 February 2011
High quality Sn-doped In2O3 (ITO) thin films have been grown by pulsed laser deposition (PLD) on glass, flexible polyethylene terephthalate (PET) and single crystal yttria stabilized zirconia (YSZ) substrates for use in organic light emitting diodes (OLEDs). Critical electrode issues for the OLED are related to the optical transparency, electrical resistivity, work function and surface roughness of the ITO film. Our research has focused on improving the properties of the ITO film to increase the efficiency of the OLED. Films were deposited using a KrF excimer laser (248nm, 30 ns FWHM) at fluences of 2 J/cm2 at substrate temperatures ranging from 1 to 100 mTorr. For ITO films (∼ 100 nm thick) deposited at the optimized conditions, a resistivity of 4.1 × 10-4 Ω-cm, 2.2 × 10-4 Ω-cm, 1.8 × 10-4 Ω-cm was observed on PET, glass and YSZ, respectively. The average film transmission in the visible range (400 - 700 nm) was about 90 % and the film surface roughness was about 0.5 nm for the film grown on glass. The Hall mobility and carrier density for ITO films (300 nm thickness) were observed to be in the range of 28 - 34 cm2/V-s and 1.0 - 1.2 × 1021 cm-3, respectively. We have used the ITO films, deposited by PLD on glass, plastic and single crystal YSZ substrates, as an anode contact in OLEDs. The OLED device performance based on PLD ITO anodes is compared with that of the device fabricated on the commercial ITO anode.