The electrical, optical and structural properties of In_<i>x</i>Zn_1−<i>x</i>O_<i>y</i>(0 <i>x</i> 1) thin films by combinatorial techniques

Abstract

Indium–zinc-oxide (IZO) compositional libraries were deposited with dc magnetron sputtering onto glass substrates at 100 °C and analysed with high throughput, combinatorial techniques. The composition range from 4 to 95 at% In for Zn was explored. A peak in conductivity with σ > 3000 (Ω cm)−1 was observed at an indium content of ~70%. The mobility exceeded 30 cm2 (V s)−1 and the carrier concentrations were greater than 8 × 1020 cm−3. Crystalline phases were observed for In concentrations less than 45% and greater than 80% with an intermediate amorphous region. The low indium content films have a zinc oxide type structure with a ZnO (002) spacing ranging from ~2.61 to 2.85 A for 4% In and 45% In, respectively. For indium contents between 82% and 95%, the In2O3 (222) spacing varied from 2.98 to 2.99 A. Regardless of the composition or the degree of crystallinity, all films showed high optical transparency with the transmission >80% across the visible spectrum.