On the Theory of the Intraband Mechanism of Single-Photon Absorption in Semiconductors, Taking into Account the Effect of Coherent Saturation
Annotatsiya
A theoretical analysis of the frequency–temperature dependence of the single-photon absorption coefficient of polarized radiation in narrow- and wide-bandgap semiconductors is conducted, considering intraband optical transitions and including the coherent saturation effect. It is shown that with a fixed radiation frequency, the single-photon absorption coefficient initially increases with temperature, reaches a maximum, and then decreases. The position of this maximum shifts to lower frequencies for both narrow- and wide-bandgap semiconductors when the temperature dependence of the bandgap width and the effective masses of holes are taken into account. In semiconductors with a zinc-blende lattice structure, accounting for the temperature variation of band parameters leads to a reduction in the amplitude of the frequency and temperature response of the single-photon absorption coefficient. As temperature rises, the absorption threshold diminishes, an effect which is especially noticeable when using the Passler bandgap model. Each type of intraband optical transition contributes differently to the frequency, temperature, and polarization dependence of the absorption coefficient for transitions involving the split-off band (SO) and light-hole (LH) band.