2D Indium Phosphorus Sulfide (In2P3S9): An Emerging van der Waals High‐k Dielectrics

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 18; no. 5; pp. e2104401 - n/a
• Main Authors: Zhu, Cheng‐Yi, Qin, Jing‐Kai, Huang, Pei‐Yu, Sun, Hai‐Lin, Sun, Nie‐Feng, Shi, Yan‐Lei, Zhen, Liang, Xu, Cheng‐Yan
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.02.2022
• Subjects: 2D materials; Degeneration; Dielectric breakdown; Epitaxial growth; Field effect transistors; high‐k dielectrics; Indium; Nanosheets; Nanotechnology; Oxide coatings; Phosphorus; Room temperature; Thickness; Two dimensional materials; van der Waals materials; high-k dielectrics; van der Waals materials; field-effect transistors; 2D materials
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202104401

2D van der Waals (vdW) semiconductors hold great potentials for more‐than‐Moore field‐effect transistors (FETs), and the efficient utilization of their theoretical performance requires compatible high‐k dielectrics to guarantee the high gate coupling efficiency. The deposition of traditional high‐k dielectric oxide films on 2D materials usually generates interface concerns, thereby causing the carrier scattering and degeneration of device performance. Here, utilizing a space‐confined epitaxy growth approach, the authors successfully obtained air‐stable ultrathin indium phosphorus sulfide (In2P3S9) nanosheets, the thickness of which can be scaled down to monolayer limit (≈0.69 nm) due to its layered structure. 2D In2P3S9 exhibits excellent insulating properties, with a high dielectric constant (≈24) and large breakdown voltage (≈8.1 MV cm−1) at room temperature. Serving as gate insulator, ultrathin In2P3S9 nanosheet can be integrated into MoS2 FETs with high‐quality dielectric/semiconductor interface, thus providing a competitive electrical performance of device with subthreshold swings (SS) down to 88 mV dec−1 and a high ON/OFF ratio of 105. This study proves an important strategy to prepare 2D vdW high‐k dielectrics, and greatly facilitates the ongoing research of 2D materials for functional electronics. Ultrathin indium phosphorus sulfide (In2P3S9) nanosheets are obtained utilizing a space‐confined epitaxy growth approach, which exhibits a high dielectric constant (≈24) and large breakdown voltage (≈8.1 MV cm−1) at room temperature. The excellent insulating properties make it suitable for integration into 2D field‐effect transistors as dielectric layer, which can provide an efficient modulation for the carrier density in a semiconducting channel.