1D-ZnO/2D-MoS₂ Van Der Waals Heterojunction Photodetectors

Photodetectors?PDs?have an important role as indispensable devices used in military,scientific research,and national life.As a condition for measuring PD,it is required to have high responsiveness,short response and recovery time,wide detection range and low cost.ZnO nanowires?NWs?and two-dimensional?2D?MoS₂ flakes have many applications in photoelectric detection due to their unique optical characteristics,high carrier mobility,and cheap manufacturing costs.However,due to the shortcomings of single materials,such as ZnO NWs and 2D MoS₂,due to the presence of air adsorption,their recovery time is longer,which restricts the further development of these two materials.Therefore,in recent years,many researchers have improved ZnO and MoS₂-based PD through various technologies.This article focuses on the preparation of ZnO NWs,the construction of ZnO and MoS₂heterojunctions,the characterization and improvement of the performance of devices in the UV-visible light.The main results are as follows:1.ZnO NWs and 2D MoS₂ flakes were prepared by chemical vapor deposition?CVD?and mechanical peeling respectively,and their morphology,structure and optical properties were measured by scanning electron microscopy?SEM?,transmission electron microscopy?TEM?,atomic force microscopy?AFM?,Raman spectroscopy and other characterization methods.The results show that the crystal structure of ZnO NWs is pure without impurities,and the number of MoS₂ layers is considerable.2.Two kinds of 2D n-type MoS₂/1D-ZnO and 2D p-type MoS₂/1D-ZnO UV-visible photodetectors were successfully constructed by a simple spin coating method.The results show that the heterojunction structure photodetector obtained by combining these two materials not only broadens the spectral response,but also further improves the light response of the device and accelerates the response and recovery speed of ZnO and MoS₂.3.The Au nanoparticles were successfully modified on the prepared heterojunction,and the responsiveness,detection speed and recovery time of theoriginal device were improved by LSPR.Compared with before the modification,the responsivity?R?and external quantum efficiency?EQE?of the modified device are greatly improved under the irradiation of 532 nm light,which is about 9.3 times,and the detection rate is 15.2 times higher than that of the device.The speed was increased from the original UV part t_rise/t_decay=0.55/19.4 s to t_rise/t_decay=0.37/5.4 s,the visible light part was increased from the original t_rise/t_decay=1.8/6.3 s to t_rise/t_decay=0.25/1.6s.