The characteristics of organic light emitting diodes with Al doped zinc oxide grown by atomic layer deposition as a transparent conductive anode

Abstract

Al doped zinc oxide (AZO) films, deposited by atomic layer deposition (ALD) were investigated for applying a transparent conductive oxide (TCO) layer as an anode for organic light emitting diode (OLED) devices. AZO films with a thickness of 100 nm were deposited at various Al atomic ratios ranging from 0 to 5% at a deposition temperature (250 degrees C). The optimum electrical properties: the carrier mobility, the resistivity, and the sheet resistance for the 2% AZO film were found to be 16.2 cm(2) V-1 s(-1), 1.5 x 10(-3) cm(-3), and 217 Omega/sq. respectively. The red OLED devices were fabricated using AZO anodes utilizing the various Al atomic ratios; the electrical and optical characteristics were then investigated. The best luminance, quantum efficiency, and current efficiency were found in the OLED device using the 2% AZO TCO; the results were 16599 cd/m(2), 8.2%, and 7.5 cd/A, respectively. (C) 2011 Elsevier B.V. All rights reserved.