Research On Terahertz Detector Based On New Semiconductor Materials

The last segment of electromagnetic spectrum that has not been widely used by humans,terahertz（THz）waves are not only in basic research fields such as the interaction between waves and substances,but also in technical fields such as security imaging,radar,communications,astronomy,atmospheric observation,and biomedicine,Have profound research significance and wide application prospects.Since the 21st century,with the rapid development of semiconductor materials and electronic technology,terahertz detection technology has made a breakthrough.However,due to sensitivity and stability issues,room temperature detector technology is not yet mature,and terahertz detectors have not been widely used.High-sensitivity and high-stability solid-state terahertz detector technology is one of the important directions of research on terahertz detection devices.In this paper,the preparation of high electron mobility transistor（HEMT）detectors based on 2D semiconductor materials such as 1T-TaS₂,1T-TiTe₂,and GaAs/AlGaAs is mainly carried out.Through material selection,the structure and size of the device are optimized to improve the performance of the detector.The preparation process of this type of detector is relatively simple,compatible with silicon-based semiconductors,and the cost is low.The detection performance is very competitive compared with the current similar devices.The research has injected new research content into the development of new terahertz detectors and provided new research results.The specific content and results of the paper mainly include the following aspects:1.The choice of response materials is the core part of the preparation of terahertz devices.We prepared the terahertz detector based on the typical semi-metallic material 1T-TiTe₂.The mechanical stripping method was used to transfer 1T-TiTe₂onto a Si/SiO₂ substrate,and the butterfly antenna structure and source-drain electrodes of the device were prepared by micro-nano processes such as ultraviolet lithography and thermal evaporation.The resistance of our terahertz detection device based on 1T-TiTe₂ material is about 500 ohms.It can reach a current response rate of1.8A/W under microwave,and its response speed can also reach the order ofμs,And the device can achieve 12mA/W response at terahertz frequency.2.Achieving high response rate detection in the terahertz band is an important goal of this research.In order to achieve this goal,we designed the logarithmic antenna structure and size,and prepared the integrated charge density wave（CDW）detection device of the antenna.At room temperature,due to the voltage drive,1T-TaS₂ changes from the NC-CDW phase to the IC-CDW phase,and the resistance decreases.Based on the phase change nature of 1T-TaS₂,we have prepared a terahertz detector device and realized the enhancement of the response rate of the terahertz detector based on 1T-TaS₂ material.3.We have prepared a terahertz detector based on GaAs/AlGaAs.The heterojunction structure composed of GaAs/AlGaAs has a very high electron mobility.The two-dimensional electron gas plasma wave can resonate with the terahertz wave.Therefore,the GaAs/AlGaAs terahertz detector can detect terahertz waves.In addition,because GaAs materials are more stable than two-dimensional materials,GaAs/AlGaAs HEMT devices can work in the air for a long time.We use the prepared GaAs/AlGaAs device to realize the imaging of continuous wave of terahertz.