Nanostructural modulation of Schottky barrier in Au/α-MoO3 heterojunction via Au nanoparticle size control

• Published in: Applied surface science Vol. 670; p. 160624
• Main Authors: Mendoza-Sánchez, Alberto R., Hernández-Rodríguez, Y.M., Casas-Espínola, J.L., Cigarroa-Mayorga, O.E.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.10.2024
• Subjects: Gold nanoparticles (AuNPs); Heterojunction system; Metal – Metal oxide SBH; Schottky barrier height; Thermal treatment; Gold nanoparticles (AuNPs); Schottky barrier height; Heterojunction system; Metal – Metal oxide SBH; Thermal treatment
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2024.160624

[Display omitted] •The size of AuNPs modifies the Schottky Barrier Height (SBH) of MoO3.•A novel method for determining SBH based on XPS in AuNPs/MoO3 systems has been developed.•AuNPs attached to MoO3 facilitate the formation of heterostructures through accessible thermal oxidation.•A new methodology has been introduced to determine the Schottky barrier in heterostructures composed of nanoparticles and nanostructures.•The alpha adjustment is introduced as a correction factor for non-ideal features in the sample. Metal-semiconductor systems, particularly those incorporating metallic nanoparticles, have garnered significant attention due to their charge transport properties and potential in solid-state applications. Thus, this study focuses on the synthesis of MoO3 microstructures through thermal oxidation, followed by the synthesis of gold nanoparticles (AuNPs) via post-thermal treatment of an Au-coated film. We systematically investigated the effect of annealing temperatures ranging from 400 °C to 700 °C on the size of the AuNPs. Utilizing techniques such as X-ray diffraction, electron microscopy, reflectance, and X-ray photoelectron spectroscopy (XPS), the physical and chemical properties of the AuNPs/MoO3 heterojunction were characterized. Findings reveal a direct correlation between the size of AuNPs and the Schottky barrier height (SBH) in the Au/MoO3 system. By considering factors such as defects, impurities, lattice mismatch, and Au diffusion—referred to as the alpha adjustment—we established that smaller AuNPs foster lower SBH values in the heterostructures. The adjusted SBH for AuNPs with diameters of 81.90 nm ± 7.21 nm, 99.44 nm ± 9.47 nm, 134.96 nm ± 15.40 nm, and 459.99 nm ± 42.63 nm resulted in a value of 0.2 eV, 0.37 eV, 1.26 eV, and 3.61 eV, respectively.