skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

This content will become publicly available on May 15, 2020

Title: Defect-Mediated Phase Transformation in Anisotropic Two-Dimensional PdSe 2 Crystals for Seamless Electrical Contacts

Abstract

The failure to achieve stable Ohmic contacts in two-dimensional material devices currently limits their promised performance and integration. Here we demonstrate that a phase transformation in a region of a layered semiconductor, PdSe 2, can form a contiguous metallic Pd 17Se 15 phase, leading to the formation of seamless Ohmic contacts for field-effect transistors. This phase transition is driven by defects created by exposure to an argon plasma. Cross-sectional scanning transmission electron microscopy is combined with theoretical calculations to elucidate how plasma-induced Se vacancies mediate the phase transformation. The resulting Pd 17Se 15 phase is stable and shares the same native chemical bonds with the original PdSe2 phase, thereby forming an atomically sharp Pd 17Se 15/PdSe 2 interface. Furthermore, these Pd 17Se 15 contacts exhibit a low contact resistance of ~0.75 kΩ μm and Schottky barrier height of ~3.3 meV, enabling nearly a 20-fold increase of carrier mobility in PdSe 2 transistors compared to that of traditional Ti/Au contacts. This finding opens new possibilities in the development of better electrical contacts for practical applications of 2D materials.

Authors:
 [1]; ORCiD logo [2]; ORCiD logo [3];  [4];  [5]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [2];  [1]; ORCiD logo [2];  [3]; ORCiD logo [2]; ORCiD logo [1]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Univ. of Tennessee, Knoxville, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Vanderbilt Univ., Nashville, TN (United States)
  4. Univ. of Tennessee, Knoxville, TN (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chinese Academy of Sciences (CAS), Beijing (China)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1530098
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 141; Journal Issue: 22; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English

Citation Formats

Oyedele, Akinola, Yang, Shize, Feng, Tianli, Haglund, Amanda V., Gu, Yiyi, Puretzky, Alexander A., Briggs, Dayrl P., Rouleau, Christopher M., Chisholm, Matthew F., Unocic, Raymond R., Mandrus, David, Meyer, III, Harry M., Pantelides, Sokrates T., Geohegan, David B., and Xiao, Kai. Defect-Mediated Phase Transformation in Anisotropic Two-Dimensional PdSe2 Crystals for Seamless Electrical Contacts. United States: N. p., 2019. Web. doi:10.1021/jacs.9b02593.
Oyedele, Akinola, Yang, Shize, Feng, Tianli, Haglund, Amanda V., Gu, Yiyi, Puretzky, Alexander A., Briggs, Dayrl P., Rouleau, Christopher M., Chisholm, Matthew F., Unocic, Raymond R., Mandrus, David, Meyer, III, Harry M., Pantelides, Sokrates T., Geohegan, David B., & Xiao, Kai. Defect-Mediated Phase Transformation in Anisotropic Two-Dimensional PdSe2 Crystals for Seamless Electrical Contacts. United States. doi:10.1021/jacs.9b02593.
Oyedele, Akinola, Yang, Shize, Feng, Tianli, Haglund, Amanda V., Gu, Yiyi, Puretzky, Alexander A., Briggs, Dayrl P., Rouleau, Christopher M., Chisholm, Matthew F., Unocic, Raymond R., Mandrus, David, Meyer, III, Harry M., Pantelides, Sokrates T., Geohegan, David B., and Xiao, Kai. Wed . "Defect-Mediated Phase Transformation in Anisotropic Two-Dimensional PdSe2 Crystals for Seamless Electrical Contacts". United States. doi:10.1021/jacs.9b02593.
@article{osti_1530098,
title = {Defect-Mediated Phase Transformation in Anisotropic Two-Dimensional PdSe2 Crystals for Seamless Electrical Contacts},
author = {Oyedele, Akinola and Yang, Shize and Feng, Tianli and Haglund, Amanda V. and Gu, Yiyi and Puretzky, Alexander A. and Briggs, Dayrl P. and Rouleau, Christopher M. and Chisholm, Matthew F. and Unocic, Raymond R. and Mandrus, David and Meyer, III, Harry M. and Pantelides, Sokrates T. and Geohegan, David B. and Xiao, Kai},
abstractNote = {The failure to achieve stable Ohmic contacts in two-dimensional material devices currently limits their promised performance and integration. Here we demonstrate that a phase transformation in a region of a layered semiconductor, PdSe2, can form a contiguous metallic Pd17Se15 phase, leading to the formation of seamless Ohmic contacts for field-effect transistors. This phase transition is driven by defects created by exposure to an argon plasma. Cross-sectional scanning transmission electron microscopy is combined with theoretical calculations to elucidate how plasma-induced Se vacancies mediate the phase transformation. The resulting Pd17Se15 phase is stable and shares the same native chemical bonds with the original PdSe2 phase, thereby forming an atomically sharp Pd17Se15/PdSe2 interface. Furthermore, these Pd17Se15 contacts exhibit a low contact resistance of ~0.75 kΩ μm and Schottky barrier height of ~3.3 meV, enabling nearly a 20-fold increase of carrier mobility in PdSe2 transistors compared to that of traditional Ti/Au contacts. This finding opens new possibilities in the development of better electrical contacts for practical applications of 2D materials.},
doi = {10.1021/jacs.9b02593},
journal = {Journal of the American Chemical Society},
number = 22,
volume = 141,
place = {United States},
year = {2019},
month = {5}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on May 15, 2020
Publisher's Version of Record

Save / Share: