Discipline: Technology and Engineering
Subcategory: Materials Science
Room: Park Tower 8216
Amrit P. Sharma - Norfolk State University
Co-Author(s): Makhes K. Behera, Norfolk State University, Norfolk, VA 23504, USA; Sangram K. Pradhan, Norfolk State University, Norfolk, VA 23504, USA; Carl E. Bonner, Norfolk State University, Norfolk, VA 23504, USA; Messaoud Bahoura, Norfolk State University, Norfolk, VA 23504, USA
The need for efficient energy utilization is driving research to harvest waste-heat, which is ubiquitous, abundant and free. Thermal energy harvesting for low power electronic devices using ferroelectric materials is one of the emerging areas of research because they possess spontaneous polarization and exhibit excellent pyroelectric coefficients. These materials are unique as they only sense time-dependent temperature change to generate electric power. We have grown lead-free BaZr0.2Ti0.8O3 (BZT)/Ba0.7Ca0.3TiO3 (BCT) multilayer heterostructures on SrRuO3 (SRO) buffered SrTiO3 (STO) single crystal substrates by optimized pulsed laser deposition (PLD) technique. The large angle x-ray scans showed only diffraction peaks from the substrate and pseudocubic reflections (100) from the multilayer heterostructures. This confirms that these films are phase pure, highly crystalline, and epitaxial in nature. The atomic force microscopy (AFM) studies indicate that the surface roughness is low (~1 nm) and that film growth is of high quality. We have developed a device with a capacitive structure of 200 nm thick BZT/BCT multilayer heterostructures sandwiched between platinum top and SRO bottom electrodes. The device demonstrates excellent pyroelectric current of ~200 nA in response to temperature fluctuation of 10 K with a period of 20 seconds using a laser of 808 nm wavelength and 150 mW power for heating. Our findings suggest that the ferroelectric thin film may be competitive with thermoelectric materials for low-grade thermal harvesting.
Funder Acknowledgement(s): This work is supported by the NSF-CREST Grant number HRD 1036494 and NSF-CREST Grant number HRD 1547771.
Faculty Advisor: Messaoud Bahoura, email@example.com
Role: Synthesis of powders, fabrication of thin films, characterization, design of experiment and their measurement.