Optoelectronic And Gas Sensitive Characterization Of Individual ZnO Nanowire

One-dimensional ZnO nanomaterial has shown great potential for applications in nanooptoelectronic devices and other fields.Its manufacture and application is the focus in the world.Beause of surface eflfect,the electrical properties are influenced by environmental,temperature and illumination significantly.Therefore,the gas sensors and ultraviolet light detection research has important significance.ZnO nanowires are manufactured by chemical-vapor deposition(CVD).Micro-grid template method is used to fabricate Ohmic contact micro-electrode of ZnO nano-devices in the text.It is a low-cost and easy fabrication method.It is the basic to study the air-sensitive and optoelectronic characterization of individual ZnO nanowire.In order to study the mechanism of individual ZnO nanowire device,O2 and air sensitive was measured.The resistance of ZnO nanowire was measured at different air pressure.It is found that ZnO nanowire's resistance and vacuum of logarithm are linear.ZnO nanowire can be made into the vacuum sensor,which mechanism is mainly surface oxygen ion desorption.Variable temperature experiments shows that the ratio of resistance at atmospheric pressure and P=10 Pa is 1000 at T=325 ?,while the ratio is 10 at room temperature.The tremendous change is owing to thermal excitation of electron for increasing carriers,which makes larger current.Photoelectric characteristic of individual ZnO nanowire is studied.It is found that ZnO is extremely sensitive to UV illumination.When the source-leak voltage is 1.5 V,photocurrent and dark current ratio is 8.3 and the result shows that the device can be applied to electric switch,etc.The decay process,after the illumination is off,exhibits a third-order exponential decay function.So we propose the mechanism of third-order exponential decay function first.The decay process,after the illumination is off,exhibits a third-order exponential decay function,with time constants of ?= 0.2 s,?2=8.5 s and ?3 =86.6 s.It can be attributed to the electron-hole recombination,and the readsorption of vaporized water and oxygen molecules.