Study On Non-volatile Phototransistor Memory Without Tunneling Dielectric Layer

The rise of information age makes information technology an indispensable part of people's daily life.Among them,memory,as the medium of information storage,information transmission and information exchange,penetrates into all fields of human society and plays an important role.At the same time,with the continuous improvement of the integration of electronic devices and the continuous development of flexible electronic intelligent devices,the traditional non-volatile memory is facing severe challenges.Therefore,it is of great significance to study new flexible non-volatile memory with high storage density,fast programming speed,good durability and low operating voltage.In this paper,the floating gate non-volatile memory based on In P@Zn S core-shell quantum dots is the main research object.The storage characteristics,data retention characteristics and endurance characteristics of the memory are systematically characterized.The theoretical analysis of the device storage mechanism is carried out to verify the great advantages of semiconductor core-shell quantum dots in floating gate non-volatile memory.On this basis,by studying the effect of organic ferroelectric high dielectric constant material P(VDF-Tr FE-CFE)on the performance of thin film transistors,this material is introduced into floating gate memory to realize the low-voltage programming operation of memory and meet the requirements of flexible devices.The main contents are as follows:Firstly,In P@Zn S QDs and Au@Si O₂ QDs are used as charge capture layers in floating gate transistor memory for a series of comparative studies and storage mechanism analysis.The results show that the In P@Zn S QDs device has the ability of fast programming,and its writing pulse width can be reduced to 1us,which is due to the carrier's fast transmission mechanism under the action of electric field.At the same time,the ability of core-shell quantum dots to store charge in positive writing/negative erasing modes is studied.Compared with traditional Au@Si O₂ QDs devices,In P@Zn S QDs devices have larger storage window(69V),stable endurance(10,000 times)and better data retention ability.In order to further improve the performance of the device,the effects of different dielectric layers on the thin-film transistor are studied.By comparing the performance of different dielectric layers in graphene thin film transistor and P3HT organic thin film transistor,it is found that the P(VDF-Tr FE-CFE)film has a large surface roughness and strong phonon scattering,which has a strong shielding effect on the charge scattering at the graphene interface.Experiments show that the P(VDF-Tr FE-CFE)dielectric layer has excellent device performance in transistors based on two-dimensional materials,which is conducive to the realization of low-voltage operation and the preparation of flexible devices.In order to study the flexible device,a flexible graphene thin film transistor based on the organic high dielectric material P(VDF-Tr FE-CFE)was prepared.After 1000 bending tests with radius of curvature of 1cm,the device still showed stable device performance.On the basis of the above,a flexible floating gate transistor non-volatile memory was designed based on the organic high dielectric material P(VDF-Tr FE-CFE)as the dielectric layer and In P@Zn S QDs as the charge trapping layer.The memory has a 6.6v memory window at 10V operating voltage,which means the device can work at low voltage.At the same time,the flexible floating gate non-volatile memory also has stable endurance characteristics and certain data retention characteristics.This paper provides a systematic test method for the characterization of memory,and reveals the working mechanism of the floating gate non-volatile memory based on the semiconductor core-shell quantum dots,which it is of great significance for the future research of high performance flexible nonvolatile memory.