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Title: Towards P-Type Conductivity in SnO2 Nanocrystals through Li Doping

Abstract

This paper examines electrical transport properties and Li doping in SnO2 synthesized by the sol–gel method. Solid-state 7Li-NMR lineshapes reveal that Li ions occupy two distinct sites with differing dynamic mobilities. The chemical exchange rate between the two sites is, however, too slow for detection on the NMR timescale. Compressed nanoparticulate films of this doped semiconductor exhibit a positive Seebeck coefficient implying a p-type conductivity. A variable-temperature direct current conductivity, over a 25–350 °C temperature range, follows an Efros–Shklovskii variable range hopping (ES-VRH) conduction mechanism (ln(ρ) versus T -1/2) at temperatures below 100 °C with a crossover to 2D Mott variable range hopping (M-VRH) (ln(ρ) versus T -1/3) conduction at temperatures above 250 °C. In a transition region between these two limiting behaviors, the dc resistivity exhibits an anomalous temperature-independent plateau. We suggest that its origin may lie in a carrier inversion phenomenon wherein the majority carriers switch from holes to electrons due to Li ion expulsion from the crystalline core and creation of oxygen vacancies generated by loss of oxygen at elevated temperatures.

Authors:
;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
979473
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Nanotechnology, 21(3):035708
Additional Journal Information:
Journal Volume: 21; Journal Issue: 3
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; DETECTION; DIRECT CURRENT; ELECTRONS; FOREIGN EXCHANGE RATE; ORIGIN; OXYGEN; TRANSPORT; VACANCIES; Environmental Molecular Sciences Laboratory

Citation Formats

Chaparadza, Allen, and Rananavare, Shankar B. Towards P-Type Conductivity in SnO2 Nanocrystals through Li Doping. United States: N. p., 2010. Web. doi:10.1088/0957-4484/21/3/035708.
Chaparadza, Allen, & Rananavare, Shankar B. Towards P-Type Conductivity in SnO2 Nanocrystals through Li Doping. United States. https://doi.org/10.1088/0957-4484/21/3/035708
Chaparadza, Allen, and Rananavare, Shankar B. 2010. "Towards P-Type Conductivity in SnO2 Nanocrystals through Li Doping". United States. https://doi.org/10.1088/0957-4484/21/3/035708.
@article{osti_979473,
title = {Towards P-Type Conductivity in SnO2 Nanocrystals through Li Doping},
author = {Chaparadza, Allen and Rananavare, Shankar B},
abstractNote = {This paper examines electrical transport properties and Li doping in SnO2 synthesized by the sol–gel method. Solid-state 7Li-NMR lineshapes reveal that Li ions occupy two distinct sites with differing dynamic mobilities. The chemical exchange rate between the two sites is, however, too slow for detection on the NMR timescale. Compressed nanoparticulate films of this doped semiconductor exhibit a positive Seebeck coefficient implying a p-type conductivity. A variable-temperature direct current conductivity, over a 25–350 °C temperature range, follows an Efros–Shklovskii variable range hopping (ES-VRH) conduction mechanism (ln(ρ) versus T -1/2) at temperatures below 100 °C with a crossover to 2D Mott variable range hopping (M-VRH) (ln(ρ) versus T -1/3) conduction at temperatures above 250 °C. In a transition region between these two limiting behaviors, the dc resistivity exhibits an anomalous temperature-independent plateau. We suggest that its origin may lie in a carrier inversion phenomenon wherein the majority carriers switch from holes to electrons due to Li ion expulsion from the crystalline core and creation of oxygen vacancies generated by loss of oxygen at elevated temperatures.},
doi = {10.1088/0957-4484/21/3/035708},
url = {https://www.osti.gov/biblio/979473}, journal = {Nanotechnology, 21(3):035708},
number = 3,
volume = 21,
place = {United States},
year = {Fri Jan 22 00:00:00 EST 2010},
month = {Fri Jan 22 00:00:00 EST 2010}
}