Performance evaluation of the indium zinc oxide (IZO) thin films for organic electroluminescent diode applications

In this report, the transparent conducting indium zinc oxide (IZO) films (60-220 nm) have been grown on hardness poly-carbonate (HPC) substrate without a post deposition annealing treatment. The direct current (dc) magnetron sputtering system was employed for the film deposition. The IZO alloy target (99.99% and 95% in purity and density, respectively) is composed of 90 wt.% of ln₂O₃ and 10 wt.% of ZnO. The electrical, optical, and structural properties of these prepared films by different dc powers, such as 50 W, 80 W and 100 W, without/with the ion-assisted deposition (IAD) technique. An optimum IZO deposition condition is developed for flexible organic light-emitting device (OLED) applications. The IZO films grown at low temperature (~ 50degC) by the dc magnetron sputtering (100-W power) with the IAD technique were used to study the electroluminescence (EL) performance of OLEDs. Under a current density of 200 (mA/cm²), the developed OLED/IZO/HPC substrate shows an excellent efficiency (5 V turn-on voltage) and a luminance of 1800 (cd/m²) in average, which is better than that measured with commercial indium-tin oxide (ITO) anodes and well above the electro-optical application standard.