Chinese Optics Letters, Volume. 23, Issue 6, 062502(2025)
Optoelectronic neuro-synaptic behaviors of antiferroelectric NaNbO3/n-GaN heterostructures
Fig. 1. Characterization of NNO/n-GaN heterostructure. (a) XRD pattern. (b) Cross-SEM image. (c) The polarization-electric (P-E) field hysteresis loop at 1 kHz. (d) Frequency-dependent dielectric constant and loss.
Fig. 2. Photoelectric performance of NNO/n-GaN heterostructure. (a) Current-voltage (I-V) hysteresis loop (the inset shows the schematic diagram of the I-V measurement). (b) Ln(I)-ln(V) curves. (c) Typical device optical switching characteristics under the 330 nm light with an intensity of 2.7 µW/mm2. (d) Energy-band diagrams of optical responses.
Fig. 3. Electronic synaptic plasticity performances of NNO/n-GaN heterostructure. (a) I-V hysteresis under consecutive dual negative voltage sweeps. (b) Synaptic potentiation and synaptic depression triggered by electric stimuli. (c) PPF phenomenon. (d) Electrical PPF index versus time interval between successive pulses and fitting curves.
Fig. 4. Photo-induced PPF behavior in NNO/n-GaN heterostructure. (a) Neural signal transmission at biological synapses and device structure diagram. (b) Typical photoresponsive characteristic under a light pulse pair with a 5 s interval. (c) Photonic PPF index versus time interval (Δt) between successive pulses.
Fig. 5. Mimicking STM and LTM using NNO/n-GaN heterostructure. (a) Schematic diagram showing the biological memory consolidation process in the human brain. STM-to-LTM transition induced by increasing (b) number and (c) frequency of pulsed light stimuli.
Fig. 6. “Learning-experience” behavior of NNO/n-GaN heterostructure. The current increase with the number of optical pulses corresponds to the learning or relearning process, while the current decay after the light stimulation represents the forgetting process. Optical pulse parameters: light wavelength: 330 nm; intensity: 2.7 µW/mm2; pulse width: 5 s; frequency: 0.2 Hz.
Fig. 7. Emulation of visual memory function in NNO/n-GaN heterostructure. (a) Image mapping of N-shaped 4 × 4 array. (b) Dynamic learning and forgetting process of conductance response image mapping.
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Huijuan Dong, Kexin Jin, Bingcheng Luo, "Optoelectronic neuro-synaptic behaviors of antiferroelectric NaNbO3/n-GaN heterostructures," Chin. Opt. Lett. 23, 062502 (2025)
Category: Optoelectronics
Received: Feb. 4, 2025
Accepted: May. 8, 2025
Published Online: Jun. 3, 2025
The Author Email: Bingcheng Luo (luobingcheng@nwpu.edu.cn)