Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 39, 2018
Previous Article Next Article

HfO2/HfS2 hybrid heterostructure fabricated via controllable chemical conversion of two-dimensional HfS2

Author affiliations

Abstract

While preparing uniform dielectric layers on two-dimensional (2D) materials is a key device architecture requirement to achieve next-generation 2D devices, conventional deposition or transfer approaches have been so far limited by their high cost, fabrication complexity, and especially poor dielectric/2D material interface quality. Here, we demonstrate that HfO2, a high-K dielectric, can be prepared on the top surface of 2D HfS2 through plasma oxidation, which results in a heterostructure composed of a 2D van der Waals semiconductor and its insulating native oxide. A highly uniform dielectric layer with a controlled thickness can be prepared; the possibility of unlimited layer-by-layer oxidation further differentiates our work from previous attempts on other 2D semiconducting materials, which exhibit self-limited oxidation up to only a few layers. High resolution transmission electron microscopy was used to show that the converted HfO2/HfS2 hybrid structure is of high quality with an atomically abrupt, impurity- and defect-free interface. Density functional theory calculations show that the unlimited layer-by-layer oxidation occurs because oxygen atoms can barrierlessly penetrate into the HfS2 surface and the extracted sulfur atoms are absorbed into the oxygen vacancy sites within HfO2 under O-rich conditions. A top-gated field-effect transistor fabricated with the converted HfO2/HfS2 hybrid structure was found to exhibit a low interface trap density Dit of 6 × 1011 cm−2 eV−1 between the HfS2 channel and the converted HfO2 dielectric, and a high on/off current ratio above 107. Our approach provides a low cost, simple, and ultraclean manufacturing technique for integrating 2D material into device applications.

Graphical abstract: HfO2/HfS2 hybrid heterostructure fabricated via controllable chemical conversion of two-dimensional HfS2

Back to tab navigation

Supplementary files

Article information


Submitted
26 Jul 2018
Accepted
24 Sep 2018
First published
27 Sep 2018

Nanoscale, 2018,10, 18758-18766
Article type
Paper

HfO2/HfS2 hybrid heterostructure fabricated via controllable chemical conversion of two-dimensional HfS2

S. Lai, S. Byeon, S. K. Jang, J. Lee, B. H. Lee, J. Park, Y. Kim and S. Lee, Nanoscale, 2018, 10, 18758
DOI: 10.1039/C8NR06020G

Social activity

Search articles by author

Spotlight

Advertisements