2D ferroelectric narrow-bandgap semiconductor Wurtzite’ type α-In2Se3 and its silicon-compatible growth
Yuxuan Jiang, Xingkun Ning, Renhui Liu, Kepeng Song, Sajjad Ali, Haoyue Deng, Yizhuo Li, Biaohong Huang, Jianhang Qiu, Xiaofei Zhu, Zhen Fan, Qiankun Li, Chengbing Qin, Fei Xue, Teng Yang, Bing Li, Gang Liu, Weijin Hu, Lain‐Jong Li, Zhidong Zhang
Abstract
Abstract 2D van der Waals ferroelectrics, particularly α -In 2 Se 3 , have emerged as an attractive building block for next-generation information storage technologies due to their moderate band gap and robust ferroelectricity stabilized by dipole locking. α -In 2 Se 3 can adopt either the distorted zincblende or wurtzite structures; however, the wurtzite phase has yet to be experimentally validated, and its large-scale synthesis poses significant challenges. Here, we report an in-situ transport growth of centimeter-scale wurtzite type α -In 2 Se 3 films directly on SiO 2 substrates using a process combining pulsed laser deposition and chemical vapor deposition. We demonstrate that it is a narrow bandgap ferroelectric semiconductor, featuring a Curie temperature exceeding 620 K, a tunable bandgap (0.8–1.6 eV) modulated by charged domain walls, and a large optical absorption coefficient of 1.3 × 10 6 /cm. Moreover, light absorption promotes the dynamic conductance range, linearity, and symmetry of the synapse devices, leading to a high recognition accuracy of 92.3% in a supervised pattern classification task for neuromorphic computing. Our findings demonstrate a ferroelectric polymorphism of In 2 Se 3 , highlighting its potential in ferroelectric synapses for neuromorphic computing.