ABSTRACT
This chapter presents novel terahertz (THz) sensing and imaging devices based on nanoelectronic materials and devices: two-dimensional (2D) semiconductors and carbon nanotube (CNT). These detectors enable THz wave sensing with high sensitivity and high spatial resolution. The chapter discusses the applications of THz measurements to materials research. The experimental data have successfully revealed the spatial properties of electrons in the two-dimensional electron gas (2DEG), which were not revealed by conventional transport measurements. THz detectors can be generally classified into three types: bolometric detection, wave detection, and quantum detection. The chapter presents the various THz detectors and discusses their advantages and disadvantages. A highly sensitive and frequency-tunable THz-photon detector using the CNT and GaAs/AlGaAs transistors has two detection mechanisms: photon-assisted tunneling (PAT), and current-peak shift. Enhancing the spatial resolution of THz imaging is one of the central issues in THz technology. There are, generally, two methods for realizing high resolution in optical imaging: solid immersion lens and near-field imaging technique.
