Characteristics of a GaAs spontaneous infrared source with 40 percent efficiency

The external quantum efficiency of a forward-biased GaAs p-n junction device selected for high efficiency measures 40.5, 32, and 7.3 percent at 20, 77, and 295°K, respectively. The optical exit path is through bulk material doped to a 10¹⁷donors/cm²level. The infrared emission is measured directly with a silicon solar cell. The effective transmissivity of the GaAs bulk device material is measured to be 42 and 8.3 percent at 77 and 295°K, respectively. The corresponding values for the internal quantum efficiency are 76 and 88 percent. The primary optical rise time measured for high level current pulsing conditions is 0.6 and 1.6 ns at 77 and 295°K, respectively.