Jump to main content
Jump to site search


The importance of phase equilibrium for doping efficiency: iodine doped PbTe

Author affiliations

Abstract

Semiconductor engineering relies heavily on doping efficiency and dopability. Low doping efficiency may cause low mobility and failure to reach target carrier concentrations or even the desired carrier type. Semiconducting thermoelectric materials perform best with degenerate carrier concentrations, meaning high performance in new materials might not be realized experimentally without a route to optimal doping. Doping in the classic PbTe thermoelectric system has been largely successful but reported doping efficiencies can vary, raising concerns about reproducibility. Here, we stress the importance of phase equilibria considerations during synthesis to avoid undesired intrinsic defects leading to sub-optimal doping. By saturation annealing at 973 K, we decidedly fix the composition in single crystal iodine-doped PbTe samples to be Pb-rich or Te-rich without introducing impurity phases. We show that, regardless of iodine concentration, degenerate n-type carrier concentrations with ideal doping efficiency require Pb-rich compositions. Electrons in Te-rich samples are heavily compensated by charged intrinsic Pb vacancy defects. From Hall effect measurements and a simple defect model supported by modern defect calculations, we map out the 973 K ternary Pb–Te–I phase diagram to explicitly link carrier concentration and composition. Furthermore, we discuss unintentional composition changes due to loss of volatile Te during synthesis and measurements. The methods and concepts applied here may guide doping studies on other lead chalcogenide systems as well as any doped, complex semiconductor.

Graphical abstract: The importance of phase equilibrium for doping efficiency: iodine doped PbTe

Back to tab navigation

Supplementary files

Publication details

The article was received on 25 Feb 2019, accepted on 01 Apr 2019 and first published on 03 Apr 2019


Article type: Communication
DOI: 10.1039/C9MH00294D
Citation: Mater. Horiz., 2019, Advance Article

  •   Request permissions

    The importance of phase equilibrium for doping efficiency: iodine doped PbTe

    J. Male, M. T. Agne, A. Goyal, S. Anand, I. T. Witting, V. Stevanović and G. J. Snyder, Mater. Horiz., 2019, Advance Article , DOI: 10.1039/C9MH00294D

Search articles by author

Spotlight

Advertisements