Dielectric and pyroelectric properties of ultrathin, monocrystalline lithium tantalate

• Monocrystalline LiTaO3 thin films with a minimum thickness of 0.4 μm were fabricated.
• Dielectric and pyroelectric properties were studied versus thickness and temperature.
• The dielectric loss factor is increased with reduction of film thickness.
• Stoichiometric LiTaO3 shows a lower performance than congruent LiTaO3.
• Pyroelectric detectors with a performance close to the limit become feasible.

Ultrathin, self-supporting lithium tantalate (LiTaO3) wafers have been fabricated out of a single crystal with a minimum thickness of about 0.4 μm using ion-beam milling. The most decisive parameters (pyroelectric coefficient, relative permittivity, and dielectric loss factor) for their use in pyroelectric radiation detectors were studied in dependence on film thickness and temperature. The potential performance of pyroelectric materials was evaluated using appropriate figures of merit. In addition, the dielectric and pyroelectric properties of stoichiometric LiTaO3 were investigated and compared to congruent LiTaO3 bulk material conventionally used for pyroelectric detectors.