ABSTRACT
Due to the fairly low band gap of the “conventional” compound semiconductors (arsenides, phosphides, see Fig. 2.3), only longer wavelength optoelectronic devices can be made from them:
infrared LEDs and lasers
red and yellow LEDs using the direct semiconductor AlGaInP for high-brightness applications
green LEDs of fairly low efficiency using the indirect semiconductor GaP by applying nitrogen doping
red lasers (λ > 630 nm) made from GaInP-AlGaInP