Controllable preparation and rapid photoelectric response of homogeneous ZnTe microspheres

Abstract

With the use of ethylene glycol as a solvent, polyvinylpyrrolidone as a surfactant and hydrazine hydrate as a reducing agent, uniform spherical ZnTe microstructures were synthesized in a homogeneous reactor by a simple solvothermal method. The influence of the synthesis conditions on the morphology was studied. The optimal conditions for preparing ZnTe microspheres of uniform size were 0.2 g PVP and 1.2 g NaOH. The ZnTe crystal nuclei quickly grew into ZnTe primary nanoparticles at the beginning of the reaction. Furthermore, ZnTe microspheres were formed by the ZnTe primary nanoparticles through the directional attachment mechanism. The photoelectrical properties of the ZnTe microspheres were investigated by fabricating a photodetector based on a ZnTe microsphere film and studying their corresponding current–voltage characteristics in the dark and under laser illumination at room temperature. Under the irradiation of 535 nm pulsed incident light with a switch cycle of 4 s, the laser power of 100 mW and bias voltage of +5.0 V, the photodetector shows a photocurrent of 0.513 μA and a responsivity of 6.72 μA W⁻¹. The ZnTe microsphere photodetector shows an obvious photoelectric signal and good stability. The rise and decay times of the photodetector are 96.93 ms and 103.57 ms, respectively, and the response time is much faster than that of the recently reported photodetectors based on ZnTe nanomaterials.