Fig. 2

Light tunable synaptic behaviors in Ta₂NiSe₅/SnS₂ device. a Schematic of the entire biological visual system. b An EPSC of Ta₂NiSe₅/SnS₂ device triggered by an optical pulse. The duration of the optical pulses is 200 ms. The power of the optical pulses from 375 to 1310 nm are 0.15 μW, 0.36 μW, 0.26 μW, 1.89 μW, 5.66 μW, 21.05 μW, and 1.19 mW. c Dependence of the EPSC triggered by an optical pulse on the pulse duration. The duration and power of the optical pulses are 200 ms and 13.26 μW. Error bars represent the standard deviation obtained from four times independent tests of Ta₂NiSe₅/SnS₂ device. d Dependence of the EPSC triggered by an optical pulse on the power of the pulses. The duration of the optical pulses is 200 ms. Error bars represent the standard deviation obtained from four times independent tests of Ta₂NiSe₅/SnS₂ device. e EPSC of Ta₂NiSe₅/SnS₂ device triggered by a pair of optical pulses with a duration of 200 ms. The interval time(△t) between the two pulses is 2 s. The power of the optical pulses from 375 to 1310 nm are 0.15 μW, 0.79 μW, 1.73 μW, 13.26 μW, 6.19 μW, 421 μW, and 1.19 mW. f Dependence of the PPF index (defined as A₂/A₁) on △t. The red solid line results from the fitting with an exponential function. g The dependence of transition from STP to LTP on the quantity of the optical pulses. The duration and interval time of the optical pulses are 200 and 200 ms, respectively. h EPSC of Ta₂NiSe₅/SnS₂ device triggered by 30 pulses. The time interval between the pulses is 200 ms. The power of the optical pulses from 375 to 1310 nm are 0.15 μW, 0.02 μW, 0.51 μW, 2.3 μW, 43.04 μW, 219 μW, and 857.77 μW. i Dependence of PSC gain on the quantity of the optical pulses. Error bars represent the standard deviation obtained from four times independent tests