Fig. 4
a A typical PPF behavior of the CdSe QDs/IGZO hybrid channel synaptic phototransistor. b The PPF index as a function of the light pulse interval (532 nm, 1 mW/cm2). c the LTP behavior of the phototransistor measured by applying 30 continuous light pulses (532 nm, 1 mW/cm2, 2 s). d The EPSC gain ratio (∆A30/∆A1) as a function of the light pulse frequency