Multiferroic behavior of the functionalized surface of a flexible substrate by deposition of Bi₂O₃ and Fe₂O₃

Abstract

Thin films of bismuth and iron oxides were obtained by atomic layer deposition (ALD) on the surface of a flexible substrate poly(4,4′‐oxydiphenylene‐pyromellitimide) (Kapton) at a temperature of 250°C. The layer thickness was 50 nm. The samples were examined by secondary‐ion mass spectrometry, and uniform distribution of elements in the film layer was observed. Surface morphology, electrical polarization, and mechanical properties were investigated by atomic force microscope, piezoelectric force microscopy, and force modulation microscopy. The values of current in the near‐surface layer varied in the range of ±80 pA when a potential of 5 V was applied. Chemical analysis was performed by X‐ray photoelectron spectroscopy, where the formation of Bi2O3 and Fe2O3 phases, as well as intermediate phases in the Bi–Fe–O system, was observed. Magnetic measurements were carried out by a vibrating sample magnetometer that showed a ferromagnetic response. The low‐temperature method of functionalization of the Kapton surface with bismuth and iron oxides will make it possible to adapt the Bi–Fe–O system to flexible electronics.

Multiferroic/Polymer Flexible Structures Obtained by Atomic Layer Deposition

“…Oxidative degradation is more common in high temperature environments, so an alternative atmosphere is required to prevent a rapid reduction in film lifetime [ 39 ]. The probable structural components of the surface area of the substrate after the influence of ozone and temperature are shown in Figure 1 , then the process of decomposition of the precursors and the formation of Bi-O and Fe-O bonds take place [ 40 ]. Inert surfaces are modified in various ways by ultrasonication with UV ozone or KOH, this mechanism has also been tested on an inert HOPG (highly oriented pyrolytic graphite) surface [ 34 ].…”

“…As can be seen on XPS, the small thickness does not allow FeO x to crystallize, the crystalline phase is formed in conjunction with Bi-O during growth and over the course of a chemical reaction [ 40 ]. The additional peaks that appeared for the BFO film in the region of 420 eV are related to 4d electrons with spin orbital splitting 3/2 and 5/2.…”

Fractal Theory in Thin Films: Literature Review and Bibliometric Evidence on Applications and Trends

“…The bibliographic coupling of institutions is con-tradictory to the results presented in Table 7; i.e., the most influential institutions in terms of the number of publication outputs and citations do not imply the most influential in terms of bibliographic coupling. The observation may be attributed to high collaborations among these four institutions with the rest of the world (for instance, see the recent research of [85] with institutions from Romania, Russia, Iran and Czech Republic). For instance, although the Chinese Academy of Sciences is highly ranked in terms of publications and citations, it has lower bibliographic coupling than the University of Johannesburg (South Africa).…”

Influence of film thickness on structural, optical, and electrical properties of sputtered nickel oxide thin films

“…The sputtering process configuration is shown schematically in Figure 1. Despite all these deposition methods, many studies have considered the properties of thin films to be dependent on the structure and morphology of the films during the nucleation and growth processes, and the effect of various factors such as deposition pressure, deposition speed, substrate structure, substrate temperature have been investigated (Achour et al, 2017;Mansouri Majd et al, 2018;Oladijo et al, 2022;Ramazanov et al, 2022;Sousani et al, 2018).…”