High efficient GaAlAs light-emitting diodes of 660 nm with a double heterostructure on a GaAlAs substrate

A new type GaAlAs light-emitting diode of 660 nm with a double heterostructure fabricated on a GaAlAs substrate has been developed. It can provide high efficiency of 8.0% and high speed response with a cut-off frequency of 20 MHz. The GaAlAs substrate is transparent at the emission wavelength of 650–660 nm, bringing about a reduction of internal absorption to increase the efficiency. The DH structure produces a high speed of response by confining carriers in the thin active layer.