Technologies and related physics of LED chips for semiconductor lighting applications

Solid-state lighting based on light emitting diodes made of compound semiconductor materials has created another revolution in the history of the lighting industry. Currently, the major factors restricting broad application of semiconductor lighting devices are the low light extraction efficiency (external quantum efficiency), low light flux (maximum operational power), overall cost per lumen, and reliability or life-time The light extraction efficiency of the chips as well as the light flux of individual devices will be discussed in connection with the chip-processing technologies and the physics involved.