Fig. 6: Image memory with vdW spectrometers.
From: Miniaturized spectrometer with intrinsic long-term image memory
a Time-resolved source-drain current of the device under alternate 635 nm laser illumination and positive gate pulse (pulse-width ~0.1 s). The blue shaded area and blue dashed lines indicate the illumination by laser and the application of the gate pulses, respectively. Vds = 1 V, Vg = 20 V, Pin = 0.2 mW/cm2. b Time-resolved Ids of the device under alternate 635 nm laser pulses and positive gate pulses (pulse-widths are both ~0.1 s). The red and blue dashed lines indicate the application of the laser pulses and gate pulses, respectively. Vds = 1 V, Vg = 40 V, Pin = 0.5 mW/cm2. c Retention characteristic of the optoelectronic memory device after applying the program light pulse (red circles, Pin = 12 mW/cm2, pulse-width ~0.1 s) and erase positive gate pulse (blue circles, amplitude 20 V, pulse-width ~0.1 s). The current ratio of program/erase state reaches 103 at Vds = 1 V and Vg = 0. The dotted vertical line represents the time when the laser pulse and gate pulse were applied. d Endurance performance test of the optoelectronic device executed with alternate light pulses (red circles, Pin = 12 mW/cm2, pulse-width ~0.1 s) and gate pulses (blue circles, amplitude 20 V, pulse-width ~0.1 s). Vds = 1 V, Vg = 0. e Schematic representation of the ‘fast mode’ of the device at Vds = 0. f Time resolved current curve of the device under periodic 635 nm laser illumination (Pin = 50 mW/cm2) at Vds = 0 and Vg = 0, showing a fast response and response time measurement of the ‘fast mode’, showing rise and decay times both of 0.43 ms. g Schematic of configuration and principle of the imaging memory system of our device. h Scanning photocurrent images of three different patterns under three different lasers. The upper panel shows the images at the moment the laser pulses is on (t = 0), and the lower panel shows the images at 5 min after the lasers were off (t = 5 min).
