Carbon Nanotube Film Field Effect Transistor Terahertz Detector With Antenna Coupling

Terahertz wave is electromagnetic wave between the infrared and the millimeter wave,which contains broad information in physics,chemistry and material construction and has a wide variety of applications prospects in space exploration,biomedical diagnostics,security and communications,and so on.Terahertz detection is one of key techniques in the development of terahertz with a core device of detector.Room-temperature and high sensitivity terahertz detection has been realized by AlGaN/GaN heterostructure high electron mobility transistor?AlGaN/GaN-HEMT?based on field-effect self-mixing mechanism.As one of new nanomaterials,s-SWCNT has been utilized to fabricate carbon nanotube film field-effect transistor?CNT-FET?and exhibit predominant characteristics on high electron mobility(10⁵ cm²?V^-1?s^-1),low ohmic contact resistance?10 k??,low threshold swing?60mV/dec?and high current on/off ratio?10⁸?,and so on.Based on field-effect self-mixing mechanism,terahertz antenna is able to induce the horizontal and vertical electric fields,respectively,and then regulate the drift velocity and concentration of the carriers and generate directional self-mixing current in the channel.Hence,CNT-FET has great potential to accomplish the realization of high sensitive terahertz detection.In order to explore self-mixing effect and high sensitive detection technology on terahertz,The design,fabrication,test and analysis of antenna-coupled s-SWCNT field-effect terahertz detectors based on self-mixing are carried out in this work.The main results of study are:1.Based on the self-mixing mechanism of CNT-TFT terahertz detector with antenna coupling,the calculating formula of the mixed photocurrent,responsivity and noise equivalent power?NEP?are deduced.2.The fabrication of CNT-TFT terahertz detector is accomplished;and then the basic parameters such as carrier mobility,carrier concentration and ohmic contact resistance per unit area are extracted by electrical testing of the device.Moreover,terahertz detection based on CNT-TFT with antenna frequency of 0.33 THz is realized in our experiment.3.Responsivity and noise characteristics of AlGaN/GaN-HEMT terahertz detectors at elevated temperatures from room-temperature to 200?are studied.Moreover,the connection between sensitivity and reponsivity and noise are also discussed in detail.In this work,the antenna-coupled CNT field-effect transistor terahertz detector is designed and fabricated successfully.Room-temperature direct detection is realized by this terahertz detector at 0.33 THz,but the cause of gate leakage and poor field-effect characteristics need to be recovered and solved to improve sensitivity in following works.