Abstract-d carrier-density dependence of electron-hole scattering in silicon investigated by optical-pump terahertz-probe spectroscopy

T. Terashige, H. Yada, Y. Matsui, T. Miyamoto, N. Kida, and H. Okamoto

Phys. Rev. B 91, 241201(R) – Published 5 June 2015

http://journals.aps.org/prb/abstract/10.1103/PhysRevB.91.241201

We measured the optical conductivity σ̃(ω) spectra of photodoped silicon by optical-pump terahertz-probe spectroscopy and analyzed them with a two-carrier Drude model. Taking into account the values of electron (hole)-phonon scattering rates previously reported in chemically doped silicon, we evaluated the electron-hole scattering rates γe-h. From 293 to 90K, the magnitudes and temperature dependence of γe-hwere successfully reproduced by a theoretical model including the effects of Rutherford scattering, Coulomb screening, and Pauli exclusion. This suggests that these three factors dominate electron-hole scattering processes in silicon. Below 90K, γe-hbecomes larger than that of the theoretical curve, which is attributable to a prolongation of the relaxation time of hot carriers.

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