ABSTRACT In this work, we report a synaptic thin film transistor (TFT) based on crystalline indium oxide (c‐In 2 O 3 ), employing a plasma‐enhanced chemical vapor deposition (PECVD) SiO 2 gate insulator (GI) and an ultrathin magnesium oxide (MgO) interlayer. Owing to high electron density c‐In 2 O 3 , the TFT with SiO 2 GI exhibits conducting behavior. In contrast, the c‐In 2 O 3 /MgO TFT demonstrates well‐defined anticlockwise hysteresis with a large memory window of 17 V, a high I ON /I OFF ratio of 10 8 , and threshold voltage of 0 V. The interlayer passivates oxygen vacancies in c‐In 2 O 3 , thereby reducing the carrier concentration. Meanwhile, mobile protons (H + ) in the GI can contribute to the hysteresis through proton‐related interfacial polarization, consistent with the capacitance response. The device successfully emulates key biological synaptic functions, including excitatory and inhibitory postsynaptic current (EPSC/IPSC), paired‐pulse facilitation (PPF), short‐term plasticity (STP), and long‐term plasticity (LTP). Note that stable synaptic weight modulation is achieved over repeated potentiation and depression cycles. The results indicate the effectiveness of the MgO interlayer for achieving CCW hysteresis and reliable synaptic operation in coplanar In 2 O 3 ‐based TFTs, compatible with SiO 2 GI.
Roy et al. (Sun,) studied this question.