Polar-surface-driven growth of ZnS microsprings with novel optoelectronic properties

Abstract

Small perturbations during the growth kinetics of low-dimensional semiconductor structures may lead to novel features, which may provide an ideal system for understanding the fundamental physics of optical phenomena in optoelectronics devices. In this study, we report deformation-free single-crystal zinc sulfide (ZnS) microsprings produced by a polar-surface-driven growth process, and we thoroughly investigate the electrical characteristics of individual ZnS microsprings under electron beam irradiation and their initial applications in ultraviolet (UV) light sensors and waveguides. The microsprings produced are formed by a block-by-block stacking process following a hexagonal screw model that does not introduce distortion into the crystal lattices. The first photodetectors designed based on a single ZnS microspring exhibit a high spectral selectivity combined with a high photosensitivity and a fast response time (<0.3 s) under 320-nm illumination, which make ZnS microsprings particularly valuable as UV-light sensors. Concurrently, excellent waveguide performance along the fiber of a single ZnS microspring (for example, ~0.13 dB μm−1 at 450 nm, and ~0.17 dB μm−1 at 520 nm) is demonstrated for the first time. The high crystal quality, the fast response to UV light and the low propagation loss exhibited by ZnS microsprings indicate that they have important potential applications in nano-optoelectronic systems. High-quality, single-crystal ZnS microsprings have been made and found to have fast responses to ultraviolet light and low propagation loss. The optoelectronic properties of one-dimensional semiconductor structures such as nanowires can be modified by bending them. Now, Tianyou Zhai and colleagues in China have grown deformation-free, single-crystal ZnS microsprings by vapor deposition involving a polar-surface-driven process. They examined the optoelectronic properties of the microsprings and found that irradiation by a high-energy electron beam increases the gain while electron-electron interactions suppress the conductivity. The researchers fabricated photodetectors based on single ZnS microsprings, which exhibited a high photosensitivity and a fast response time to ultraviolet illumination. Furthermore, the microsprings had an excellent waveguide performance. These properties make ZnS microsprings promising for components for future micro/nano-optoelectronic systems. Herein, we reported deformation-free single crystal ZnS microsprings produced by the polar-surface-driven growth process with novel optoelectronic properties for the first time. The entire spring is synthesized by a block-by-block stacking process following a hexagonal screw model, without introducing distortion in crystal lattices. The electrical characteristics of individual ZnS microsprings under electron beam irradiation and their potential applications in UV light sensor and waveguides were thoroughly investigated. The high crystal quality, fast response to UV light and the low propagation loss indicate ZnS microsprings will have important applications in future optoelectronic systems.