Room-Temperature Ferroelectric Epitaxial Nanowire Arrays with Photoluminescence

Abstract

The development of large-scale, high-quality ferroelectric semiconductor nanowire arrays with interesting light-emitting properties can address limitations in traditional wide-bandgap ferroelectrics, thus serving as building blocks for innovative device architectures and next-generation high-density optoelectronics. Here, we investigate the optical properties of ferroelectric CsGeX 3 (X = Br, I) halide perovskite nanowires that are epitaxially grown on muscovite mica substrates by vapor phase deposition. Detailed structural characterizations reveal an incommensurate heteroepitaxial relationship with the mica substrate. Furthermore, photoluminescence that can be tuned from yellow-green to red emissions by varying the halide composition demonstrates that these nanowire networks can serve as platforms for future optoelectronic applications. In addition, the room-temperature ferroelectricity and ferroelectric domain structures of these nanowires are characterized using second harmonic generation (SHG) polarimetry. The combination of room-temperature ferroelectricity with photoluminescence in these nanowire arrays unlocks new avenues for the design of novel multifunctional materials.

Centimeter-Scale CdS Single-Crystal Nanoscale-Thick Films via Chemical Vapor Deposition for High-Performance Photodetectors

“…Initially, when the precursor of CdS reaches the mica surface, it prefers to nucleate at the sites with higher energy on mica to reduce the system energy, which results in the early-stage formation of CdS nanosheets that have a relatively larger thickness due to the longer growth time (see the brighter sheets in Figure b and steps 1 and 2 schematically shown in Figure e). Because the surface nonuniformity of mica is usually resulted from the nonuniform distribution of K + ions formed when it is cleaved, the surface energy difference of various sites should be small. , With the time extension, therefore, the growth of the early formed sheets and the formation of new ones can simultaneously take place, which leads to the different thickness sheets (see the darker sheets in Figure b and step 3 schematically shown in Figure e). Interestingly, the sheets formed at both stages have the same lateral growth orientation, which indicates an identical growth mechanism.…”