Transistorized 4h-SiC Thermoelectronic Photodetector Based On Surface Plasmon Effects

Photodetectors based on the first-generation and second-generation semiconductor materials(silicon(Si),indium gallium arsenicde(In Ga As),mercury telluride,germanium,and lead sulfide)have been developed for many years and can basically meet the needs of most applications.However,the tradition photodetectors face great challenges in extreme environments such as high temperatures.Silicon carbide(SiC),as a representative of the third generation semiconductors,has the characteristics of high critical displacement energy,high mobility,good stability,and good thermal conductivity,which makes it a competitive material for developing high-performance photodetectors.For SiC photoelectric detector,SiC transistor can effectively amplify the device current,and wide-spectrum transistor-type photodetectors are urgently needed in national life and military applications,.SiC material cannot absorb the photon whose energy is greater than the band gap of SiC.The wide-spectrum photodetectors can be realized by preparing the heterostructures consisted of SiC and other materials or introducing the metal micro-nano structure into the device.And it was found in the research that the interface optimization between the gate electrode and the semiconductor also has a great influence on the device performance.In this thesis,the third-generation semiconductor material 4H-SiC is used as the research object.The transistor-type 4H-SiC photodetector is fabricated by magnetron sputtering and atomic layer deposition techniques.First,different top electrode materials were selected to prepare a standard transistor-type 4H-SiC photodetector,and its performance was characterized,so that the metal Ag with better performance was selected as the top electrode material.Subsequently,Au nanoparticles were introduced into the device.The absorption and morphology of the particles were characterized,the parameters of Au particles with the best performance were determined,and a transistor-type 4H-SiC thermionic photodetector was prepared.The connection method was used to systematically characterize the device performance.From the characterization results,it can be seen that the current in the horizontal direction of the device is effectively amplified,and the response range of the device is broadened to the 4H-SiC non-absorbing band,and the responsivity remains at 10 A/W in the400 – 850 nm band.Finally,on the basis of standard devices,the interface between the gate electrode and 4H-SiC is doped with aluminum oxide,and its thickness is optimized,so as to achieve the effect of interface optimization,and by applying between the source and drain electrodes In the method of large bias voltage,the top electrode is annealed,so that Ag nanoparticles are formed on the surface of the electrode,which in turn stimulates the surface plasmon effect,and generates hot electrons that are injected into the semiconductor,and the performance of the device is characterized.,the responsivity at 800 nm can still be maintained at 10 A/W.It lays the foundation for the preparation of transistor-type 4H-SiC thermionic photodetectors with optimized interface layer.