Understanding the core physics and fabrication techniques behind modern semiconductor devices

Wide bandgap semiconductors (e.g. GaN) and semiconductor heterostructures (e.g. AlxGa1−xN/GaN) are the key wide bandgap semiconductor technologies in the twenty-first century. The one-dimensional photonic structures (OPSs) play increasingly important roles in the design and fabrication of light-emitting diodes (LEDs), lasers, and semiconductor detectors. Conventional LEDs and semiconductor lasers based on planar designs, however, suffer light extraction inefficiency in LEDs and spatial hole burning (SHB) and “hard” thermal fold catastrophes in lasers. These limitations can be overcome effectively with the use of OPSs which are formed by building the semiconductor heterostructures or directly integration with the photonic crystal design. This chapter presents the state-of-the-art designs and fabrication techniques of OPSs based on oriented growth of group III-nitride semiconductors for LED and laser applications (Amuru et al., 2022; Jouppi et al., 2023; Ning et al., 2024).

In the mid-twentieth century and the mid-1990s, the development of the technology and/or materials for a light source transitioned from gas discharge to early semiconductor devices (p–n junction LEDs), to the first generation of semiconductor lasers (e.g. InGaAlP lasers), and to visible and ultraviolet (UV) LEDs and lasers based on the wide bandgap semiconductors (e.g. GaN). As a result, remarkable improvements on economically important applications such as full-color flat panel displays and Blu-ray players. The state-of-the-art group III-nitride semiconductor technologies grown on the low-defect-density c-plane sapphire substrates and their vertical configurations (e.g. flip-chip structures) have enabled revolutionizations of numerous solid-state lighting (SSL) applications and civilian and military optoelectronic devices. Zero-thickness adjustable photonic crystal (PC).

The optical and electronic properties of two-dimensional (2D) materials are reviewed focusing on Monolayer and few-layer transition metal dichalcogenides. The conceptual understanding of how the dimensionality of the material affects its light absorption and emission, charge transport, and energy relaxation mechanisms is summarized. The strongly localized charge carriers excited by high-energy photoexcitation influence the optical response of 2D materials in important ways, a feature that could be explored for applications in optoelectronics. 2D semiconductors represent an important step toward the realization of miniaturized and portable electronics, optoelectronics, and photonics. 2D layered materials are attractive alternatives to bulk counterpart semiconductors for nano-sized devices due to the high on/off current ratio, ultrahigh carrier mobility, as well as gating effect (Shastri et al., 2020; Samuel, 2024).