InGaAs/GaAs, strained-layer superlattice (SLS), junction photodetectors, LED´s, injection laser´s, and FET´s for optoelectronic IC applications

A set of optoelectronic devices including p-n junction photodetectors, emitters (both an LED and a stripe-geometry, injection LASER), and a gain device have been fabricated from In0.2Ga0.8As/GaAs strained-layer superlattice (SLS) material. The photodetectors have demonstrated a peak external quantum efficiency at zero volts reverse bias(uncorrected for surface reflection) of 50% at 770nm and an optical absorption edge at 1050nm. Both the LED and injection LASER have peak, room temperature, emission wavelengths near 1020nm. The LASER exhibited cw, 77K operation at 976nm with a threshold current of 95mA, the first reported cw operation of an InGaAs/GaAs SLS LASER. Previously reported studies of prototype, double-gate, modulation-doped FETs (channel length = 2.5 µm) have demonstrated peak intrinsic transconductances of 120mS/mm at room temperature and 190mS/mm at 77K. These encouraging photodetector, LED, LASER, and FET results demonstrate that useful optical and electronic devices can be fabricated from mismatched materials and that the InGaAs/GaAs SLS system is an attractive candidate for integrated optoelectronic applications.