Terahertz (THz) technology has been used for almost two decades for investigations of nanomaterials, including nanocrystals, nanoparticles, nanowires, nanotubes, or 2D crystals. Detecting and manipulating the THz radiation is of high interest for medical imaging, security checks, quality control, nano- and opto-electronic devices, atmospheric and space chemistry, etc. The current THz detector technology, however, often lacks good sensitivity, speed, spectral range, or room-temperature operation. The work being carried out addressed our understanding of this subject in two areas on which we focused synergistically. The first relates to the development of engineered materials and structures from 2D MXene to 3D graphene, which represents a new way to build materials with novel properties, particularly in the THz electromagnetic wave range. The second is on the use of materials as device, such as THz photodetector and modulator.
Terahertz technology lies at the heart of modern technology for its potential applications in spectroscopy, imaging, and wireless communications. The terahertz wave is easily transmitted through most non-metallic and non-polar media because its photon energy is so low; for this reason, it also poses no threat to human health. Therefore, detecting and manipulating the THz radiation is of high interest for different applications. The materials and structures developed in this project (MXene sheets & Graphene aerogels) are desirable and are expected to promote THz light absorption and modulation properties. By using a low-cost technique, we were able to create an MXene THz photodetector with precise detectivity, good responsivity, and a consistent, fast photoswitching response. It is proven that a straintronic modulator based on 3D graphene can modulate THz radiation absorption and reflection in real-time over a broad range of 0.1–3 THz. These findings open up a world of hitherto undiscovered physical phenomena with enormous promise for radar, electromagnetic, and THz imaging applications.
To address the conception of novel devices made of MXene sheets with enhanced light-matter interaction, we designed a structural architecture of MXene which populates the sample interaction area with specifically arranged 2D sheets (by multilayer and few-layer arrangements) where the THz light is exposed to every atom. This made it possible for the complete photoactive assembly to absorb as many photons as possible, resulting in the highest possible generation of photocurrent. A 3D graphene straintronic approach for real-time THz modulation allows on-demand tuning between electromagnetic shielding and stealth in a single device. This multifunctional dynamic modulator uses strain-induced changes in atomic bond configurations, enabling efficient THz radiation absorption, reflection, and transmission, offering vast potential for advanced applications.
