Interface engineering for a stable chemical structure of oxidized-black phosphorus: Via self-reduction in AlOx atomic layer deposition

Dae Kyoung Kim, Jimin Chae, Seok Bo Hong, Hanbum Park, Kwang Sik Jeong, Hyun Woo Park, Se Ra Kwon, Kwun Bum Chung, Mann Ho Cho

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Abstract

We evaluated the change in the chemical structure between dielectrics (AlOx and HfOx) grown by atomic layer deposition (ALD) and oxidized black phosphorus (BP), as a function of air exposure time. Chemical and structural analyses of the oxidized phosphorus species (PxOy) were performed using atomic force microscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, first-principles density functional theory calculations, and the electrical characteristics of field-effect transistors (FETs). Based on the combined experiments and theoretical investigations, we clearly show that oxidized phosphorus species (PxOy, until exposed for 24 h) are significantly decreased (self-reduction) during the ALD of AlOx. In particular, the field effect characteristics of a FET device based on Al2O3/AlOx/oxidized BP improved significantly with enhanced electrical properties, a mobility of ∼253 cm2 V-1 s-1 and an on-off ratio of ∼105, compared to those of HfO2/HfOx/oxidized BP with a mobility of ∼97 cm2 V-1 s-1 and an on-off ratio of ∼103-104. These distinct differences result from a significantly decreased interface trap density (Dit ∼ 1011 cm-2 eV-1) and subthreshold gate swing (SS ∼ 270 mV dec-1) in the BP device caused by the formation of stable energy states at the AlOx/oxidized BP interface, even with BP oxidized by air exposure.

Original languageEnglish
Pages (from-to)22896-22907
Number of pages12
JournalNanoscale
Volume10
Issue number48
DOIs
Publication statusPublished - 2018 Dec 28

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)

Cite this

Kim, D. K., Chae, J., Hong, S. B., Park, H., Jeong, K. S., Park, H. W., Kwon, S. R., Chung, K. B., & Cho, M. H. (2018). Interface engineering for a stable chemical structure of oxidized-black phosphorus: Via self-reduction in AlOx atomic layer deposition. Nanoscale, 10(48), 22896-22907. https://doi.org/10.1039/c8nr06652c