Differences between nanoscale structural and electrical properties of AZO:N and AZO used in polymer light-emitting diodes.
Conducting atomic force microscopy and scanning surface potential microscopy were adopted to investigate the nanoscale surface electrical properties of N-doped aluminum zinc oxide (AZO:N) films that were prepared by pulsed laser deposition (PLD) at various substrate temperatures. Experimental results demonstrated that when the substrate temperature is 150 degrees C and the N(2)O background pressure is 150 mTorr, the N-dopant concentration on the surface is optimal. In addition, the root-mean-square roughness value of the film surface, the low contact current (<400 nA) conducting region as a percentage of the total area, and the mean work function value are 1.43 nm, 96.9%, and 4.88 eV, respectively, all of which are better than those of the optimal AZO film made by PLD. This result indicates that N-doped AZO films are better for use as window materials in polymer light-emitting diodes.
Chen
Sy-Hann
SH
Department of Applied Physics and Institute of Optoelectronics and Solid State Electronics, National Chiayi University, Chiayi 600, Taiwan. shchen@mail.ncyu.edu.tw
Yu
Chang-Feng
CF