ABSTRACT
This chapter focuses on fundamental mechanisms underlying the light-emitting diode (LED) operation that should be included in the simulation models. LED heterostructures, chips, and lamps are considered separately, with a discussion on links between them. Due to the breakthroughs in technological advances in the development of III-nitride semiconductors made in the early 1990s, visible LEDs occupy the dominant sector of the optoelectronics market. Any LED structure consists of a stack of epitaxial layers grown in a certain sequence on a substrate of choice. State-of-the-art LEDs utilize rather complex essentially 3D chip designs aimed at achieving various goals: providing a uniform carrier injection into the active regions at minimum series resistance, efficient light extraction from the LED dice, and efficient heat removal from the active region. Crowding is the effect of the current density localization inside the LED die around the streamlines with minimum path resistance.
