GaAs Infrared source

A diffused junction GaAs diode has been developed for use as a fast, high-efficiency, infrared source. The diode is forward biased with the light being generated by the recombination of minority carriers in the semiconductor bulk. The device is a P⁺-N structure with a spaced contact covering a minor portion of the N-type face of the wafer through which the radiation is emitted. The infrared radiation is characterized by a sharply defined peak at slightly less than band gap (E gap=1.43ev at 300° K) and a broad peak at about 1.0 ev. The measured radiation pattern closely follows that expected of a flat plate, i.e., the intensity decreases as the cosine of the angle from the normal. The diode V-I curve is characterized by exp (qV/2kT) at low current (up to 1 ma), exp (qV/kT) at moderate current (5-50 ma) and series IR drop at high current (above 200 ma).