Chapters authored
Broadband Terahertz Emission from Photoconductive Devices
This chapter explores the terahertz (THz) emission from biased semiconductor photoconductive devices. The photoconductive device is an optoelectronic device that is able to emit broadband THz radiation under the optical excitation, by an ultrafast laser, in the existence of a bias field. This chapter explains the basic principle of photoconductive devices with focusing on the main device components, being the photoconductive material and the photoconductive structure. Then, various materials and structures are discussed toward improving the performance of the photoconductive THz emitters. Furthermore, the main limitations and considerations are presented with insight into the different saturation and screening effects due to the bias field and pump fluence. Ultimately, the recent advances and studies of photoconductive THz emitters are presented in terms of material and structure, including the quantum dots, the nanostructure, the use of dielectric materials, and the grating structure on the photoconductive surfaces.
Part of the book: Intelligent Electronics and Circuits
Two-Dimensional Materials for Terahertz Emission
The demand for ultrahigh-speed, lightweight, low-cost, and defect-tolerant electronic devices drives the industry to switch to terahertz (THz) technologies. The use of two-dimensional (2D) materials has massively increased in THz applications due to their appealing electronic and optoelectronic properties, including tunable bandgap, high carrier mobility, wideband optical absorption, and relatively short carrier lifetime. Several 2D-material-based emitters, modulators, and detectors have been fabricated and examined. In this context, considerable research has been going on for 2D-material-based THz emitting sources, including materials and device structure to understand the electronics and optoelectronics mechanisms occurring in the THz region. This chapter focuses on the 2D-material-based emitters with insights into the background, the physical principle of photoconductive THz emitters, the 2D materials’ properties, and the research trends in the fabrication and characterization of the THz sources based upon 2D materials.
Part of the book: Trends in Terahertz Technology