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Title: Ultrafast carriers dynamics in filled-skutterudites

Journal Article · · Applied Physics Letters
DOI:https://doi.org/10.1063/1.4922399· OSTI ID:22412551
;  [1];  [2]
  1. School of Mechanical Engineering and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)
  2. Chemical and Materials Systems Laboratory, GM Global R and D, Warren, Michigan 48090 (United States)

Carrier dynamics of filled-skutterudites, an important class of thermoelectric materials, is investigated using ultrafast optical spectroscopy. By tuning the wavelength of the probe laser, charge transfers at different electronic energy levels are interrogated. Analysis based on the Kramers-Kronig relation explains the complex spectroscopy data, which is mainly due to band filling caused by photo-excited carriers and free carrier absorption. The relaxation time of hot carriers is found to be about 0.4–0.6 ps, depending on the electronic energy level, and the characteristic time for carrier-phonon equilibrium is about 0.95 ps. These studies of carrier dynamics, which fundamentally determines the transport properties of thermoelectric material, can provide guidance for the design of materials.

OSTI ID:
22412551
Journal Information:
Applied Physics Letters, Vol. 106, Issue 23; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
Country of Publication:
United States
Language:
English