Progress of AlGaInP red laser diodes and beyond

High-performance AlGaInP red laser diodes (LDs) and light emitting diodes (LEDs) play a key role in the light sources for displays, sensors, medicals, plants, and optical information areas. AlGaInP crystals grown by metal organic chemical vapor deposition method have to solve many issues such as band gap narrowing, low p-carrier concentration, 2-dimentional crystal growth, and hillocks on the crystal surface. We found an innovative solution that introduces (100) GaAs substrates with misorientation towards the [011] direction at the world-first in 1988. This paper presents about development history of AlGaInP laser diodes, some merits by using the substrate, and high performances laser diodes, which are fabricated by combining the substrates and strain compensated multiple quantum wells.