Multilayered BCST/PZT Thin Films on GaN Substrate for Ultraviolet Photodetector Applications

In the realm of photodetection, there has been growing interest in Ferroelectric/semiconductors heterostructures due to the interfacial charge coupling resulting from ferroelectric polarization. In this study, we created a thin film consisting of alternating layers of Ba0.86Ca0.14Ti0.9Sn0.1O3 and PbZr0.52Ti0.48O3 (referred to as BCST/PZT) using a sol-gel growth method on a (0001) GaN/c-sapphire template. Our objective was to examine the impact of these films on the optoelectronic properties of ferroelectric/GaN heterojunctions. Our findings indicate that the BCST/PZT multilayer films possess improved ferroelectric properties. Furthermore, the multilayer structure demonstrates outstanding optoelectronic performance compared to the individual BCST/GaN or PZT/GaN structures, particularly within the 1V to 3V bias range. Notably, the multilayer thin film/GaN devices exhibit a responsivity of 121.4mA/W and a detectivity of 1.44 × 1011 Jones under a 1V bias voltage. In contrast to other GaN-based materials documented in the literature, our straightforward sol-gel techniques yielded devices exhibiting UV photodetection characteristics that are either comparable to or superior than those reported.