Year: 2026
Type: article
Abstract: ABSTRACT Ferroelectric domain walls (DWs) host unique functionalities, including a photovoltaic effect. However, the wide bandgaps of conventional oxide ferroelectrics limit their solar absorption. In contrast, 2D semiconductors, with inherently narrower band gaps, are promising alternatives, yet the photovoltaic behavior of their DWs remains largely unexplored. Here, we investigate DWs in SnS, a ferroelectric 2D semiconductor. Multidomain SnS crystals were synthesized on mica substrates via physical vapor deposition, and the Curie temperature of this phase was determined using high‐temperature second‐harmonic generation measurements. Mechanical switching of ferroelectric domain orientations was demonstrated, and the atomic‐scale DW configurations were identified using high‐angle annular dark‐field scanning transmission electron microscopy in combination with synchrotron X‐ray microbeam diffraction. Photocurrent measurements reveal a distinct contribution from DWs to the photovoltaic response. Notably, this contribution strongly depends on the spatial arrangement of DWs relative to the electrodes, exhibiting behavior fundamentally different from that observed in oxide ferroelectrics. These findings highlight the distinct functional role of DWs in 2D ferroelectrics, establishing a new avenue for narrow‐bandgap ferroelectric optoelectronics.
Source: Advanced Functional Materials
DOI: 10.1002/adfm.77741
Authors: Ryo Nanae, Satsuki Kitamura, Tomonori Nishimura, Kaito Kanahashi, Tomoaki Kameda, Katsunori Wakabayashi, Redhwan A Moqbel, Ting‐Hsuan Wu, Kung‐Hsuan Lin, Yosuke Ogawa, Eiji Nishibori, Keisuke Shinokita, Kazunari Matsuda, Jui‐Han Fu, Vincent Tung, Takashi Taniguchi, Kenji Watanabe, Kosuke Nagashio
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,790
OpenAlex ID: W7203638017