InAlGaP microactivity LEDs on Ge substrates emitting at 640nm with compress
ively strained MQW active layers have: been fabricated. The external quantu
m efficiency for a nonencapsulated MCLED was 5.2% at 4mA and the device emi
tted 1.9mW at 20mA and nearly 8mW optical output power at an injection curr
ent of 100mA.