The Electrical, Optical and Structural Properties of InxZn1-xOy (0<x<1) Thin Films by Combinatorial Techniques

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 Å 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 Å. Regardless of the composition or the degree of crystallinity, all films showed high optical transparency with the transmission >80% across the visible spectrum.