Research On Two-dimensional Material Quantum Capacitance Device And Its Heterogeneous Integration

In recent years,two-dimensional（2D）materials have attracted great interest due to their novel optical,electrical,thermal and mechanical properties.Many new concepts,new principles and new functions of 2D materials devices have been put forward,which have an innovative impact on the development of micro nano electronics.The 2D materials have a strong field effect and photoelectric effect due to its atomic thickness,so it has a strong application potential for the next generation of ultra-thin electronic and optoelectronic devices.Although the 2D materials and devices have made great progress recently,there are still many problems to be solved in order to make them practical use.Research on the quantum capacitance of 2D material stacking devices and the photoelectronic properties of 2D material heterojunctions are the main directions for exploring the potential of 2D materials.Therefore,the principle,manufacturing technology and performance of 2D material devices need to be studied deeply.In this thesis,the preparation and transport properties of 2D quantum capacitance and its heterojunction devices are studied.The main contents are summarized as follows:（1）The application of 2D materials at terahertz（THz）frequencies was studied,and a theoretical model of graphene photo-controlled quantum capacitors in a graphene-2D material insulator-graphene（DGGIG）structure was proposed for THz frequency and phase modulation.The simulation results show that photoexcitation can change the frequency and phase of the plasma oscillation waves.（2）The quantum capacitance and the channel resistance of graphene play an important role in the performance of graphene field-effect transistors（GFETs）.The experimental results show that the phase of output signal changes under the influence of the quantum capacitance and channel resistance in GFETs.The quantum capacitance and channel resistance are controlled by the gate voltage.This phenomenon is analyzed theoretically and the simulation model of phase shift is established.（3）A bipolar phototransistor device based on vertical Au/graphene/Mo S₂ van der Waals heterojunction is studied.The device can be mass produced by using a simple silicon semiconductor process.Au is not only used as emitter,but also as a functional material,Mo S₂ as collector and graphene as base.The maximum photoresponse is16500 A/W and the photocurrent generation rate is 1.48 x10-4 A/s.（4）A silicon-based CMOS readout circuit for two-dimensional material heterojunction devices is studied.The circuit can be used to process the photocurrent signal by heterogeneous integration with the 2D devices.The recovery process of two-dimensional material heterojunction photodetectors has a serious tailing phenomenon.In order to solve this problem,the readout circuit of photodetector can be designed in CMOS process to accelerate the process of carrier recombination and improve the response rate.