A novel soft deposition methodology for textured ZnO:Al thin films as efficient transparent conductive oxide layers

In this paper, a novel soft deposition methodology was developed for depositing Al-doped ZnO (AZO) thin films as Transparent Conducting Oxide (TCO) layer. The new proposed methodology could help in reducing the process time and cost that could subsequently be useful for industrial scalability purposes. In general, the effect of substrate distance (dTS), Ar gas flow (F_Ar), and sputtering power (P_W) were analyzed on structural, morphological, optical, and electrical properties. Films exhibiting the best electrical values (3.2 × 10⁻⁴ Ω*cm, 21.3 cm² V⁻¹ s⁻¹, and 9.2 × 10²⁰ cm⁻³) were deposited at F_Ar of 5 sccm, P_W of 45 W, and room temperature. Additionally, AZO thin films deposited inside the high-density zone (HDZ, dTS < 6 cm) of the plasma sputtering exhibited a textured surface with crater-like morphology, and it was found to be more evident in films deposited at reduced F_Ar (5 sccm) and low P_W (45 W) values. The present methodology could be of great interest for the low-cost production of AZO thin films with a textured surface obtained in a one-step DC sputtering process for modern optoelectronic applications such as flexible solar cells and electroluminescent devices.