The Gas Ion Gate Modulated By Triboelectric Nanogenerator And Its Application In ZnO Thin Film Novel Resistance Switch Memory

ZnO is a kind of new type of semiconductor material,its exciton binding energy at room temperature is about 60 meV.At the same time,it has a wide forbidden band width about 3.37 eV.ZnO has special properties in terms of electrical properties,band structures and lattice structure,etc,which has been widely investigated in recent years.Up to now,ZnO nanostructure materials have been applied in various research fields,such as light emitting diodes,field effect transistors,gas sensors,resistive switch memories,transparent conductive films,solar cell,batteries and flat panel displays.With the development of science and technology,higher requirements are proposed for various device,as a result,new technology is required to be developed to improve the performances of the device.ZnO thin film has large surface area and rich surface states.The gas molecules adsorbed on the surface can modify the surface charge and surface state,which can change the work function and energy band structure of the thin film,and then change the electron mobility.The adsorbed molecules play an important role in regulating the electrical transport properties and the performance of optoelectronic devices.However,the effective mean to directly regulate gas adsorption is still lack.Therefore,this paper proposes a method of ionizing air by triboelectric nanogenerator?TENG?,which can be used to regulate the electrical transport characteristics of ZnO thin film and develop new type resistance switch device.The paper includes the following parts.In chapter 1,the research background is briefly introduced.We mainly list out the basic characteristics of ZnO and its developments and applications in the field of semiconductor devices.The important effect of surface state on the photoelectric transmission characteristics of ZnO and the research work on surface state regulation are introduced.The researches show that the gas adsorption is an important surface state.However,the effective mean to directly regulate gas adsorption is still lack.Hence,it is necessary to develop an effective method to control the surface state of ZnO thin film.Our previous report about the air discharge induced by TENG is also introduced,which is the basis for the gas ion gate modulation technology proposed in this paper.In chapter 2,the gas ion gate modulation technology is established,and its effect on the electrical transport properties of ZnO thin film is investigated.The ZnO thin film is deposited on Au electrode pairs by atomic layer deposition method.The mechanism of controlling ZnO thin film surface state by gas ion gate based on TENG-induced air discharge is investigated.The main positive ion gate is N₂⁺and the main negative ion gate is O₂^-.Gas ion gate regulates ion adsorption on ZnO thin film surface,which can make the current of ZnO thin film to be repeatedly changed between 10^-10 A and 10^-2 A repeatedly,and the on-off ratio can reach up to 8 orders of magnitude.The transition from the low resistance state to a high resistance state is realized.Under positive gas ion gate regulation,the response time of the device is 0.25 s;under negative gas ion gate regulation,the recovery time of the device is 0.12 s.Based on these results,a reversible and nonvolatile resistance switch device controlled by bipolar gas ion gate is developed.In chapter 3,the gas ion gate and the UV light illumination are combined to modulate the ZnO thin film.Firstly,the resistance switch characteristics of ZnO thin film under the control of negative ion gate and UV light irradiation are studied.The resistive switch is in a low resistance state under the control of UV light.That's because UV light can make oxygen remove from ZnO thin film surface.The resistance switch is in a high resistance state under the control of negative ion gate.That's because it can make O₂^-directly adsorbed on ZnO thin film surface.In addition,the device can achieve triplet resistance state by combining UV light and positive/negative gas ion gate,which can be used to develop multiple states resistance memory device.Through the study in this paper,a gas ion gate technology based on TENG are established,which can be used to effectively modulate the electrical transport characteristics of ZnO thin films.Based on the gas ion gate method,a new type of resistance switch memory is developed.The results in this paper provide a new method for controlling the surface state of nanostructures,which has potential applications in developing novel electronic/optoelectronic devices with high performances.