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Tailoring Nickel Oxide Thin Films: Comparative Study of Oxidizing Agents in Thermal and Plasma-Enhanced Atomic Layer Deposition

Year: 2024

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide Thermal atomic layer deposition (TALD) and plasma atomic layer deposition (PALD) were used for producing thin NiO x films from nickel(II) acetylacetonate Ni(acac) 2, employing different oxidizing agents (deionized water H 2 O, ozone O 3, and molecular oxygen O 2 ). The films were deposited at 300 °C (TALD) and 220 °C (PALD) over glass substrates; their physical and chemical properties were considerably influenced by the choice of oxidizing agents. In particular, ALD(H 2 O) samples had a low growth per cycle (GPC) and a high concentration of defects. The best NiO x parameters were achieved with PALD(O 2 ), featuring high GPC (0.07 nm/cycle), high optical transparency in the visible region, electrical resistivity (1.18 × 10 4 Ω·cm), good carrier concentration (8.82 × 10 13 cm –3 ), and common mobility (5.98 cm 2 /V·s). The resulting NiO x films are polycrystalline and homogeneous in thickness and composition. According to ultraviolet photoelectron spectroscopy (UPS), work function φ and the valence band maximum E V can be tuned by the choice of the coreactant employed, with variations of up to ∼1 eV between TALD and PALD synthesis. Our results suggest that PALD permits one to achieve a better energy band alignment of NiO x and CsFAMAPbBrI perovskite, which is promising for solar cell applications.

Source: ACS Omega

DOI: 10.1021/acsomega.4c06606