Heterojunctions of Topological Insulator and Metal organic frameworks for THz detection applications (TI-MOF-TERA)

Today, x-ray detection techniques are widely used in the homeland security, such as airport surveillance and custom activities, and in the medical diagnostics. However, x-rays are ionizing, can provoke cancer like diseases and, moreover, they are unable to detect fabric, plastic and concealed hazardous materials. The terahertz (THz) technology has a potential to solve these problems; however, mainly due to the low photon energy of THz waves, it is still difficult to accomplish high-speed and sensitive room temperature THz detection. The proposed work aims to advance the THz detection technology by exploring exciting opto-electronic properties of topological insulators (TIs), metal organic frameworks (MOFs) and their interfaces. I will focus the research on the design and fabrication of heterojunctions consisting of TI thin films and semiconducting two-dimensional MOFs and on the optimization of their electronic properties and interaction strength with THz radiation. To address the enhancement of light-matter interaction in these novel devices I will vary the chemical composition of MOF layers, thus enabling the control of their crystalline order and of the coupling between organic and inorganic components. TIs surface properties will then enhance the charge carrier transport at the interface due to topological protection against the carrier scattering. These ingredients will allow tuning and optimization of the photocurrent generation upon absorption of THz photons, i.e. of the photodetection process. The project will answer questions of the physical mechanisms of charge carrier transport in MOFs and at TI-MOF interfaces and of the key parameters for an enhancement of optoelectronic properties in Ti-MOF heterojunctions.