Transparent conducting aluminum-doped zinc oxide thin films for organic light-emitting devices

Aluminum-doped zinc oxide (AZO) thin films (similar to 3000 Angstrom) with low electrical resistivity and high optical transparency have been grown by pulsed-laser deposition on glass substrates without a postdeposition anneal. Films were deposited at substrate temperatures ranging from room temperature to 400 degrees C in O-2 partial pressures ranging from 0.1 to 50 mTorr. For 3000-Angstrom-thick AZO films grown at room temperature in an oxygen pressure of 5 mTorr, the electrical resistivity was 8.7 x 10(-4) Omega cm and the average optical transmittance was 86% in the visible range (400-700 nm). For 3000-Angstrom-thick AZO films deposited at 200 degrees C in 5 mTorr of oxygen, the resistivity was 3.8 x 10(-4) Omega cm and the average optical transmittance in the visible range was 91%. AZO films grown at 200 degrees C were used as an anode contact for organic light-emitting diodes. The external quantum efficiency measured from these devices was about 0.3% at a current density of 100 A/m(2). (C) 2000 American Institute of Physics. [S0003-6951(00)02603-6].