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Title: Non-metallic dopant modulation of conductivity in substoichiometric tantalum pentoxide: A first-principles study

Here, we apply density-functional theory calculations to predict dopant modulation of electrical conductivity (σ o) for seven dopants (C, Si, Ge, H, F, N, and B) sampled at 18 quantum molecular dynamics configurations of five independent insertion sites into two (high/low) baseline references of σo in amorphous Ta 2O 5, where each reference contains a single, neutral O vacancy center (V O 0). From this statistical population (n = 1260), we analyze defect levels, physical structure, and valence charge distributions to characterize nanoscale modification of the atomistic structure in local dopant neighborhoods. C is the most effective dopant at lowering Ta 2O x σ o, while also exhibiting an amphoteric doping behavior by either donating or accepting charge depending on the host oxide matrix. Both B and F robustly increase Ta 2O x σ o, although F does so through elimination of Ta high charge outliers, while B insertion conversely creates high charge O outliers through favorable BO 3 group formation, especially in the low σ o reference. While N applications to dope and passivate oxides are prevalent, we also found that N exacerbates the stochasticity of σ o we sought to mitigate; sensitivity to the N insertion site andmore » some propensity to form N-O bond chemistries appear responsible. Finally, we use direct first-principles predictions of σ o to explore feasible Ta 2O 5 dopants to engineer improved oxides with lower variance and greater repeatability to advance the manufacturability of resistive memory technologies.« less
Authors:
 [1] ;  [1] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
SAND2017-3842J
Journal ID: ISSN 0021-8979; 652423
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 121; Journal Issue: 21; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
OSTI Identifier:
1361046
Alternate Identifier(s):
OSTI ID: 1366554

Bondi, Robert J., Fox, Brian P., and Marinella, Matthew J.. Non-metallic dopant modulation of conductivity in substoichiometric tantalum pentoxide: A first-principles study. United States: N. p., Web. doi:10.1063/1.4983850.
Bondi, Robert J., Fox, Brian P., & Marinella, Matthew J.. Non-metallic dopant modulation of conductivity in substoichiometric tantalum pentoxide: A first-principles study. United States. doi:10.1063/1.4983850.
Bondi, Robert J., Fox, Brian P., and Marinella, Matthew J.. 2017. "Non-metallic dopant modulation of conductivity in substoichiometric tantalum pentoxide: A first-principles study". United States. doi:10.1063/1.4983850. https://www.osti.gov/servlets/purl/1361046.
@article{osti_1361046,
title = {Non-metallic dopant modulation of conductivity in substoichiometric tantalum pentoxide: A first-principles study},
author = {Bondi, Robert J. and Fox, Brian P. and Marinella, Matthew J.},
abstractNote = {Here, we apply density-functional theory calculations to predict dopant modulation of electrical conductivity (σo) for seven dopants (C, Si, Ge, H, F, N, and B) sampled at 18 quantum molecular dynamics configurations of five independent insertion sites into two (high/low) baseline references of σo in amorphous Ta2O5, where each reference contains a single, neutral O vacancy center (VO0). From this statistical population (n = 1260), we analyze defect levels, physical structure, and valence charge distributions to characterize nanoscale modification of the atomistic structure in local dopant neighborhoods. C is the most effective dopant at lowering Ta2Ox σo, while also exhibiting an amphoteric doping behavior by either donating or accepting charge depending on the host oxide matrix. Both B and F robustly increase Ta2Ox σo, although F does so through elimination of Ta high charge outliers, while B insertion conversely creates high charge O outliers through favorable BO3 group formation, especially in the low σo reference. While N applications to dope and passivate oxides are prevalent, we also found that N exacerbates the stochasticity of σo we sought to mitigate; sensitivity to the N insertion site and some propensity to form N-O bond chemistries appear responsible. Finally, we use direct first-principles predictions of σo to explore feasible Ta2O5 dopants to engineer improved oxides with lower variance and greater repeatability to advance the manufacturability of resistive memory technologies.},
doi = {10.1063/1.4983850},
journal = {Journal of Applied Physics},
number = 21,
volume = 121,
place = {United States},
year = {2017},
month = {6}
}

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