Ultrafast carriers dynamics in filled-skutterudites

作者：Guo Liang; Xu Xianfan^*; Salvador James R

来源：Applied Physics Letters, 2015, 106(23): 231902.

DOI：10.1063/1.4922399

• Characteristic time
• Electronic energy levels
• Filled skutterudites
• Free carrier absorption
• Photoexcited carriers
• Thermo-Electric materials
• Ultrafast carriers
• Ultrafast optical spectroscopy

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.

• 出版日期2015-6-8