Interband optical excitation of space-charge waves in high-resistance semiconductors

A fairly complete theory is proposed for trap recharging waves upon their optical excitation under conditions of dominant interband transitions. It is demonstrated that the occurrence of interband transitions reduces the role of trapping centers existing in the crystal and the carrier lifetime. This leads to a decrease in the lifetime of trap recharging waves and can result in their complete disappearance as eigenmodes of electron oscillations in the semiconductor crystal. It is shown that a large number of specific cases can occur depending on the illumination intensity and the ratio of recombination parameters. The physical meaning of the effective trap concentration and its relation to the screening length of the internal electric field are discussed.