  We propose and fabricate a dual-emitter light-induced neuromorphic device
composed of two light-induced devices with a common collector and base. Two
InGaN multiple quantum well diodes (MQW-diodes) are used as the emitters to
generate light, and one InGaN MQW-diode is used as the common collector to
absorb the emitted light. When the presynaptic voltages are synchronously
applied to the two emitters, the collector demonstrates an adding together of
the excitatory post synaptic voltage (EPSV). The width and period of the two
input signals constitute the code to generate spatial summation and recognition
effects at the same time. Experimental results confirm that temporal summation
caused by the repetitive-pulse facilitation could significantly strengthen the
spatial summation effect due to the adding together behavior when the
repetitive stimulations are applied to the two emitters in rapid succession.
Particularly, the resonant summation effect occurs at the co-summation region
when the two repetitive-pulse signals have a resonant period, which offers a
more sophisticated spatiotemporal EPSV summation function for the dual-emitter
neuromorphic device.
