PDC2023-145856-I00_Dataset

Abstract

[ENG]The terahertz (THz) spectral range lies between the microwave and infrared regions of the electromagnetic spectrum, generally referring to the range between 0.1 and 10 THz. THz technology is of great interest due to its specific properties. Many materials, such as paper and plastic, are transparent to this radiation, enabling inspection and security operations. Many substances have a 'fingerprint' (a characteristic spectrum) in the THz range, making THz radiation a powerful tool for spectroscopic applications. Due to its low photon energy (approximately one million times lower than X-rays), THz radiation is non-ionising and therefore poses no danger to humans. This research project aimed to develop, demonstrate and prepare for transfer a new THz detector prototype capable of competing effectively with existing technologies. The new system was designed modularly so that sensor chips manufactured using different technologies can be employed. In particular, the project has employed two cutting-edge technologies: silicon FinFET transistors and graphene-based transistors. The detection process uses two transistors and is based on plasmon oscillation in a two-dimensional electronic system within an FET channel. This enables EM radiation in the terahertz range to be detected, in accordance with the Dyakonov–Shur theory. These sensors offer several advantages: low cost; a faster response time than other detectors (e.g. bolometers and pyroelectrics); operation at room temperature; scalability; integration into CMOS silicon technology for FinFETs; and compatibility with graphene-based transistors. Graphene field-effect transistors (GFETs), which were developed at the USAL, are highly attractive for THz applications thanks to their high channel mobility (over 100,000 cm²/Vs at room temperature) and efficient light-matter interaction. GFETs have been fabricated with various types of integrated antenna to improve responsivity. FinFETs constitute the latest generation of commercial transistors with ultra-short gate topology, making them excellent candidates for building THz detectors that are almost ready for the market, with the potential for integration of read-out circuitry. The devices were measured in the 0.15–5 THz range and between 4 and 300 K. In particular, the figures of merit, responsivity and NEP (noise equivalent power), were determined.