Sub-10 nm Tunable Hybrid Dielectric Engineering on MoS2 for Two-Dimensional Material-Based Devices

5 years ago

Sub-10 nm Tunable Hybrid Dielectric Engineering on MoS2 for Two-Dimensional Material-Based Devices

Jiyoung Kim, Robert M. Wallace, Qingxiao Wang, Jaebeom Lee, Hui Zhu, Luigi Colombo, Antonio T. Lucero, Arul Vigneswar Ravichandran, Moon J. Kim, Lanxia Cheng

The successful realization of high-performance 2D-materials-based nanoelectronics requires integration of high-quality dielectric films as a gate insulator. In this work, we explore the integration of organic and inorganic hybrid dielectrics on MoS₂ and study the chemical and electrical properties of these hybrid films. Our atomic force microscopy, X-ray photoelectron spectroscopy (XPS), Raman, and photoluminescence results show that, aside from the excellent film uniformity and thickness scalability down to 2.5 nm, the molecular layer deposition of octenyltrichlorosilane (OTS) and Al₂O₃ hybrid films preserves the chemical and structural integrity of the MoS₂ surface. The XPS band alignment analysis and electrical characterization reveal that through the inclusion of an organic layer in the dielectric film, the band gap and dielectric constant can be tuned from ∼7.00 to 6.09 eV and ∼9.0 to 4.5, respectively. Furthermore, the hybrid films show promising dielectric properties, including a high breakdown field of ∼7.8 MV/cm, a low leakage current density of ∼1 × 10^–6 A/cm² at 1 MV/cm, a small hysteresis of ∼50 mV, and a top-gate subthreshold voltage swing of ∼79 mV/dec. Our experimental findings provide a facile way of fabricating scalable hybrid gate dielectrics on transition metal dichalcogenides for 2D-material-based flexible electronics applications.

Publisher URL: http://dx.doi.org/10.1021/acsnano.7b04813

DOI: 10.1021/acsnano.7b04813