Study of Localization of Carriers in Disordered Semiconductors by Femtosecond Spectroscopy

 

M. Willander, Dept of Physics, Gothenburg Univ.

Yu.E. Lozovik, Inst. of Spectroscopy, Troitsk, Moscow

 

 

Abstract- A new method for determination of the mobility edge in disordered semiconductors by femtosecond pump-supercontinuum probe spectroscopy is presented. The method is based on the determination of the spectral dependence of a streched exponential relaxation in awide spectral range of probing, (1.6-3.2 eV). The method is demonstrated for porous silicon. It is shown that the relaxation parameters for porous silicon have essential spectral dependence. The spectral dependence of the stretched exponential index gives unique information on existence and position of the mobility edge in disordered materials, and thus may be used as effective tool in manifestation of the transition from localized to delozalized relaxation regime on the femtosecon time scale.

 

Reference:

1. Yu.E. Lozovik A. Dobryakov, S. Kovalenko, S. Merkulova, S. Volkov and M. Willander, Laser Physics, Vol. 12. No. 4, pp 802-811, 2002