Preparation Of Graphene Quantum Dots-Indium Based Thin Film Transistors By All-Solution Method And Application Exploration In Logic Circuits

With the rapid development of flat panel display technology,semiconductor integrated circuits and the emergence of new electronic products,the application of thin film transistors（TFTs）in the field of high-definition displays continues to expand.Indium-based oxides are favoured by researchers for properties such as high mobility,good transparency and optoelectronics,and are used as excellent channel materials for display devices.Graphene quantum dots（GQDs）have promising applications in photocatalysis,optoelectronic devices and biosensors due to their unique optical properties.Based on the advantages of both,compounding indium-based oxides with GQDs can further improve the performance of indium-based TFTs.Therefore,it is of great scientific significance to carry out the construction and performance tuning of GQDs-doped indium-based TFTs.In this thesis,GQDs-modified indium-based oxide and gate dielectric materials were prepared based on the all-solution method,and graphene quantum dot-indium-based thin-film transistors were constructed.The effects of GQDs doping on the electrical parameters and stability of indium-based TFTs were analyzed in depth,and the applications of graphene quantum dot-indium-based thin-film transistors in logic circuits were explored.The main results obtained in this thesis are as follows.1.High quality graphene quantum dot powders and ZrO_x high-k gate dielectric films were prepared based on a total solution method.The annealing temperature-dependent behavior of the leakage current and dielectric properties of Al/ZrO_x/Si MOS devices was investigated.It was found that the ZrO_x films had the lowest surface roughness（0.552 nm）and lower leakage current density(7.51 x 10^-8Acm^-2)at an annealing temperature of 600°C.The smooth ZrO_xfilm surface acquisition facilitates fast carrier transport and ensures low leakage currents.The results show that high-quality graphene quantum dots and ZrO_x film acquisition provide an experimental basis for the integration of excellent TFTs.2.GQDs-In₂O₃/ZrO_x TFTs devices were constructed based on the all-solution method,and the effects of GQDs doping on the electrical properties and stability of In₂O₃/ZrO_x TFTs were systematically investigated.It was found that GQDs doping could effectively modulate the device performance of TFTs.At a GQDs doping concentration of 0.2 mg/ml,GQDs-In₂O₃/ZrO_xTFTs exhibited excellent electrical properties,including a largeμ_FE(34.02 cm²V^-1s^-1),a high I_on/I_off（4.55×10⁷）,a small SS(0.08 Vdec^-1)and an integrated resistive loaded inverter showing a high voltage gain of 10.63.The results show that GQDs modified In₂O₃ TFTs prepared by the all-solution method can contribute to the development of transparent,low-cost oxide thin-film electronic devices.3.GQDs-α-InGaO/ZrO_x TFTs were constructed by the full solution method.The effects of different doping concentrations of GQDs on the microstructure,surface morphology,thermal behavior,optical properties and oxygen vacancy content ofα-InGaO films were systematically investigated;the effects of different doping concentrations of GQDs on the interfacial quality,electrical properties and stress stability of the biased light of the TFTs were analyzed.The results show that GQDs help to reduce the interfacial defect states and improve the bias light stress stability of the devices.The results show that the preparation of GQDs-IGO TFTs based on the all-solution method provides great theoretical support and experimental help for the future application of quantum dot-based TFTs in the field of optoelectronics.4.The GQDs-α-InGaZnO/ZrO_x TFTs were prepared based on the total solution method.results show that GQDs-doped GQDs-α-InGaZnO/ZrO_x TFTs with a doping concentration of0.5 mg/m L exhibit good stability under bias and light conditions:including a mobility of up to35.91 cm²V^-1s^-1,a switching current ratio of 5.04×10⁸ of switching current ratio,and a sub-threshold swing of 0.11 Vdec^-1.The constructed GQDs-α-InGaZnO/ZrO_x resistor-loaded unipolar inverters show good dynamic behavior and a high gain of 9.4.Low frequency noise analysis verifies the effective suppression of defects within the films by the GQDs.The results show that the all-solution method is a simple,reliable and universal approach to integrate GQDs-α-InGaZnO/ZrO_x with low cost and low power consumption into future quantum dot-based optoelectronic devices.5.Based on the optimization of GQDs-α-InGaZnO/ZrO_x TFTs by the plasma oxidation process combined with the total solution method,the effect of the cycle number of oxygen plasma treatment on the surface morphology and chemical bonding state of GQDs-α-InGaZnO thin films was systematically investigated.The results show that oxygen plasma treatment can reduce the roughness of the films,improve the flatness of the films and effectively reduce the oxygen vacancy content in the films.The results show that oxygen plasma treatment is an effective method to reduce the defects and improve the quality of the films,and has important applications in the preparation of high performance GQDs-IGZO TFTs by the all-solution method.