Self‐Poled Heteroepitaxial Bi_(1−x)Dy_xFeO₃ Films with Promising Pyroelectric Properties

Abstract

Pyroelectric materials are very promising for thermal energy harvesting applications. To date, lead‐based systems are the foremost studied materials in this field. A facile and simple metal organic chemical vapor deposition route is applied for the fabrication of lead‐free, high quality, epitaxial Bi(1−x)DyxFeO3 (x = 0, 0.06, 0.08, 0.11) thin films deposited on conductive SrTiO3:Nb (100) single crystal substrates. The films are studied by structural, morphological, compositional, and functional characterization. The correlation between the Dy‐doping amount and the dielectric properties is thoroughly investigated. Unipolar polarization–electric field loops and permittivity measurements show the important impact of Dy on ferroelectric, dielectric, and pyroelectric properties. Dy doping increases considerably the dielectric response, but much more the pyroelectric coefficient, up to a concentration of 8% Dy. The films are self‐poled, which is an ideal situation for pyroelectric applications. The best figure of merit for pyroelectric energy harvesting, FE, is 82 J m−3 K−2, showing a factor increase of 2.6 as compared to the undoped film of the sample series. It constitutes a factor 4.5 improvement as compared to previous results obtained on BiFeO3 based thin films.

Growth of Samarium-Substituted Epitaxial Bismuth Ferrite Films by Chemical Vapor Deposition

“…High-quality films in the thickness range of 450–500 nm have been grown with excellent stoichiometry control. Significant improvement in the piezoelectric coefficient of 8% Dy-substituted BFO has been observed approaching close to the PZT system . Capability of Dy substitution to tune the bandgap of BFO has also been demonstrated.…”

“…Significant improvement in the piezoelectric coefficient of 8% Dy-substituted BFO has been observed approaching close to the PZT system. 25 Capability of Dy substitution to tune the bandgap of BFO has also been demonstrated. Increasing Dy substitution is shown to lower the bandgap of BFO.…”

A multifunctional oriented nanocrystalline Pb0.91La0.06Zr0.8Ti0.2O3 relaxor ferroelectric thin film for chip power and thermal management

“…On the contrary, the cooling process is opposite to the heating process, resulting in the generation of a reverse electric field in the external circuit. 50,51 A measurement system has been constructed to characterize the pyroelectric properties of the PLZT thin film, as shown in Fig. 6d.…”

Material strategies to enhance the performance of piezoelectric energy harvesters based on lead-free materials

“…Epitaxial growth of BiFeO 3 by different deposition techniques (MOCVD, PLD or MBE) has been mainly studied by using single crystal substrates, such as SrTiO 3 with or without SrRuO 3 bottom electrode, and conductive Nb: SrTiO 3 [180,[216][217][218][219]. The BFO film orientation in pseudo-cubic settings matches the one of SrTiO 3 ((100) pc , (110) pc and (111) PC , for the corresponding hexagonal orientations see table 2).…”