Electrical, optical, and topographical properties of RF magnetron sputtered aluminum-doped zinc oxide (AZO) thin films complemented by first-principles calculations

Abstract

The fabrication of an efficient electron transport layer (ETL) with high conductivity and transparency is of significant interest. Aluminum doped zinc oxide (AZO) is an established ETL candidate due to its excellent conductivity and transparency, especially in the visible–near infrared (Vis–NIR) spectral range. Herein, we attempt to understand AZO properties by both experimental and computational approaches, as far as these methodologies permit. As part of our approach, we have deposited AZO thin films using radio frequency sputtering technique under two different sets of conditions, batch-I (150, 175, and 200 W; 0.2 mTorr; 20 min) and batch-II (70 W; 2 mTorr; 75 min). And, we have studied the structural, morphological, topographical, electrical, and optical properties of thus deposited films. The results are complemented by first-principles calculations based on the density functional theory (DFT) performed over a 2 × 2 × 2 and 3 × 2 × 2 supercell of wurtzite ZnO, to assess the effect of one aluminum atom substitution on the structural, electronic, and optical properties of the solid. We could discuss, thus, obtained computational results by comparing with the experimental measurements through a reliable construction of aluminum doping percentage models (3.12 and 2.08 at.%).