HfSe2 and ZrSe2: Two-dimensional semiconductors with native high-kappa oxides

作者：Mleczko, Michal J.; Zhang, Chaofan; Lee, Hye Ryoung; Kuo, Hsueh-Hui; Magyari-Kope, Blanka; Moore, Robert G.; Shen, Zhi-Xun; Fisher, Ian R.; Nishi, Yoshio; Pop, Eric^*

来源：Science Advances, 2017, 3(8): e1700481.

DOI：10.1126/sciadv.1700481

• FIELD-EFFECT TRANSISTORS
• OPTICAL-PROPERTIES
• MOS2 TRANSISTORS
• PERFORMANCE
• SILICON
• OXIDATION
• DENSITY
• HETEROSTRUCTURES
• THICKNESS
• CONTACTS

The success of silicon as a dominant semiconductor technology has been enabled by its moderate band gap (1.1 eV), permitting low-voltage operation at reduced leakage current, and the existence of SiO2 as a high-quality "native" insulator. In contrast, other mainstream semiconductors lack stable oxides and must rely on deposited insulators, presenting numerous compatibility challenges. We demonstrate that layered two-dimensional (2D) semiconductors HfSe2 and ZrSe2 have band gaps of 0.9 to 1.2 eV (bulk to monolayer) and technologically desirable "high-k" native dielectrics HfO2 and ZrO2, respectively. We use spectroscopic and computational studies to elucidate their electronic band structure and then fabricate air-stable transistors down to three-layer thickness with careful processing and dielectric encapsulation. Electronic measurements reveal promising performance (on/off ratio > 10(6); on current, similar to 30 mu A/mm), with native oxides reducing the effects of interfacial traps. These are the first 2D materials to demonstrate technologically relevant properties of silicon, in addition to unique compatibility with high-k dielectrics, and scaling benefits from their atomically thin nature.

• 出版日期2017-8
• 单位中国人民解放军国防科学技术大学