학회 | 한국재료학회 |
학술대회 | 2021년 가을 (11/24 ~ 11/26, 경주 라한호텔) |
권호 | 27권 2호 |
발표분야 | G. 나노/박막 재료 분과 |
제목 | Optoelectronic Synapse Device based on HfO2/InGaZnO Double-layered Structure for Brain-inspired Neuromorphic System |
초록 | Brain-inspired sensory devices are one of the components essential for entirely implementing a neuromorphic intelligent system. For instance, optoelectronic synapse emulating synaptic plasticity in an optical manner can contribute to photo-neuromorphic computing and artificial visual perception. Optoelectronic neuromorphic devices, therefore, have attracted much interest due to the high-density process of information, low-power consumption, and low crosstalk. Nevertheless, there remain challenging issues to realize reliable and flexible optoelectronic synaptic functions. In this study, we demonstrated a double-layered based HfO2/IGZO transistor. We studied the effect of HfO2 layer on InGaZnO (IGZO) transistors. Furthermore, its optical synapse function was analyzed. Under the light illumination, threshold voltages in all of the devices were shifted to negative voltage. To evaluate photo synaptic function of HfO2/IGZO device, incident light of 455 nm with intensity of 100 μW/cm2 was selected. Postsynaptic current (PSC) of the double-layered synapse device increased when the light was incident, indicating that the synapse device was activated by light pulse stimuli. Long-term potentiation (LTP) characteristic was enhanced by addition of the HfO2 layer. The optoelectronic synapse device showed different habitual behavior in excitatory postsynaptic current along with light conditions, indicating high tunability under diverse light stimulus conditions. To understand the phenomenon more deeply, effective density of states was calculated from the photo-current decay curve of each device. The development of the novel optoelectronic device structure would pave the road toward artificial photonic neuromorphic systems. |
저자 | 오세영1, 조병진2 |
소속 | 1Department of Advanced Material Engineering, 2Chungbuk National Univ. |
키워드 | |