Huge gain in pyroelectric energy conversion through epitaxy for integrated self-powered nanodevices

• Published in: Nano energy Vol. 41; pp. 43 - 48
• Main Authors: Moalla, Rahma, Vilquin, Bertrand, Saint-Girons, Guillaume, Le Rhun, Gwenael, Defay, Emmanuel, Sebald, Gael, Baboux, Nicolas, Bachelet, Romain
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2017; Elsevier
• Subjects: Condensed Matter; Energy conversion; Epitaxy; Extrinsic contribution; Integration; Materials Science; Physics; Pyroelectricity; Integration; Pyroelectricity; Extrinsic contribution; Epitaxy; Energy conversion
• ISSN: 2211-2855; 2211-2855
• DOI: 10.1016/j.nanoen.2017.09.001

Polycrystalline (textured) and epitaxial 500nm thick Pb(Zr0.52Ti0.48)O3 (PZT) layers have been monolithically integrated in metal-insulator-metal structure on silicon in order to compare their pyroelectric properties, both statically (under stabilized temperatures) and dynamically (when submitted to temperature transient as a pyroelectric device should work). The films have roughly the same out-of-plane orientation, and thus a similar out-of-plane remnant ferroelectric polarization around 12μC/cm2. Whereas their static pyroelectric coefficients are similar (around −470μCm−2 K−1), the dynamic pyroelectric coefficient of the epitaxial layer is about one order of magnitude larger than that of the polycrystalline layer (−230 vs −30μCm−2K−1). This causes an important difference on the densities of converted pyroelectric energy by almost two orders of magnitude (1 vs 1.5 10−2mJ/cm3 per cycle for temperature variations of ∼6K). This difference is explained here by the counterbalanced extrinsic pyroelectric contribution arising from the domain walls motion in the dynamical measurements. Extrinsic pyroelectric contribution appears almost twice larger on polycrystalline layer than on epitaxial layer (+430 vs +250μCm−2K−1). These results are crucial for further design of advanced integrated pyroelectric-based nanodevices. [Display omitted] •Epitaxial PZT layer yields pyroelectric energy conversion two orders of magnitude larger than polycrystalline counterpart.•Pyroelectric extrinsic contribution is discriminated through static and dynamic measurements.•Extrinsic pyroelectric contribution due to domain wall motion appears detrimental for pyroelectric properties.•Extrinsic pyroelectric coefficient is almost twice larger with polycrystalline layer than epitaxial layer.•1 mJ/cm3 per cycle with 6 K temperature variations can be reached with epitaxial layers, enough to power nanodevices.