The fellowship resulted in the demonstration of the cumulative effect of mechanical and light exposure on a ferroelectric material. It was demonstrated that in an optically active ferroelectric, both light exposure and applied mechanical stress could be used to obtain an electrical output (See Figure 1 for set-up). It was discovered that the mechanical load helps in achieving an improved photo response (See Figure 2 for comparison). This was attributed to nanoscale polarization switching of the regions of similar polarizations (known as domains). It was anticipated that the phenomena could also work in an opposite manner where optical switching could help in modulating the state of polarization and thus resulting in mechanical stress-induced enhanced electrical output in a ferroelectric. However, not many studies focus on light passing through the sample while it is exposed to mechanical stress which is the fundamental principle of the acousto-optic modulators. Acousto-optic modulators exploit surface acoustic waves generated by using high-frequency operated inter-digited transducers (IDT). I performed calculations for various IDT designs based on BaTiO3 thin films and single crystals. However, the difficulty in device fabrication due to the charging issue while performing electron-beam lithography motivated us to modify the design and go for photolithography. This helped in learning that science has its challenges, and one should be prepared to consider alternatives until the technological bottlenecks are surpassed. Parallel to this, the action investigated ferroelectric thin films for synaptic devices. Surprisingly, significant similarities were found between structurally distinct films of the same material which was modeled using a two-stage nucleation-limited switching (2S NLS) model (Figure 3). Finally, information on potential halide perovskite materials for neuromorphic computing, memory, and optical switching applications was compiled and disseminated in the form of a review article. The article talked about large optical cross-sections, high photoconductance contrast, large carrier diffusion lengths, and mixed electronic/ionic transport mechanisms which makes this class of materials attractive for memory elements and neuromorphic devices.
Overall, the project has resulted in six journal articles (3 published including one review article, 2 submitted for publication, and 1 in the final stage of preparation) and over 14 conferences, meetings, seminars, and invited talks across the globe. These have impacted scientific progress in the field. Moreover, all disseminated knowledge through publications, seminars, and talks will guide young researchers interested in working on neuromorphic computing devices. Moreover, the talks and seminars (both online and on-site) were made accessible to the general public and undergraduate as well as school-going students in particular. The motivation behind the fellowship project and its societal impact has surely triggered scientific curiosity among the audience with an expectation to encourage them to pursue science as fun with responsibility.
