HfSe<sub>2</sub> and ZrSe<sub>2</sub>: Two-dimensional semiconductors with native high-κ oxides.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28819644.
- Also identified by DOI 10.1126/sciadv.1700481 and PMC identifier 5553816.
- Licence recorded as CC BY-NC.
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Abstract
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 SiO<sub>2</sub> 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 HfSe<sub>2</sub> and ZrSe<sub>2</sub> have band gaps of 0.9 to 1.2 eV (bulk to monolayer) and technologically desirable "high-κ" native dielectrics HfO<sub>2</sub> and ZrO<sub>2</sub>, 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<sup>6</sup>; on current, ~30 μA/μm), 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-κ dielectrics, and scaling benefits from their atomically thin nature.