Measurement of the frequency-dependent conductivity in sapphire.
Electron transport of photoexcited single-crystal sapphire (alpha-Al2O3) is characterized by terahertz time-domain spectroscopy. The complex conductivity displays a Drude-type frequency dependence, which yields carrier scattering rates and densities. Carrier scattering is dominated by interactions with acoustical and optical phonons at low and high temperatures, respectively, and follows Matthiessen's law over the measured temperature range of 40-350 K. The results, including low-temperature mobilities >10000 cm(2)/V s, are compatible with a large-polaron description of the conduction electrons.
Shan
Jie
J
Departments of Physics and Electrical Engineering, Columbia University, 538 West 120th Street, New York, New York 10027, USA.
Wang
Feng
F
Knoesel
Ernst
E
Bonn
Mischa
M
Heinz
Tony F
TF