Physics and possibility for new device applications in GaN-based p-i-n structures

Band diagram of GaN-based p-i-n structures containing InGaN/GaN multiple quantum wells is discussed in the presence of an external electric field. Carrier lifetime, photocurrent, and photoluminescence intensity as a function of applied voltage can be understood based on the potential diagram. These structures effectively generate "spatially localized strain pulse", which is not present in other materials such as in GaAs-based p-i-n structures. The mechamisms of the generation and propagation of the strain pulse and their relevance with the piezoelectricity of GaN are discussed. These structures with InGaN/GaN multiple quantum wells also produce electromagnetic radiation of 0.11 THz, which is absent in GaN-based double heterostructures.