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The free-carrier absorption in n-type InSb films has been investigated for carriers confined in quasi-two-dimensional (2D) semiconductors with the nonparabolic energy band of electrons. We discuss the effect of phonon scattering on the free-carrier absorption coefficient (~) for both deformation-potential coupling and piezoelectric coupling. ~ is found to depend on the photon polarization relative to the direction normal to the quasi-2D structure, the photon frequency, the film thickness, and the temperature. ~ could be complex due to the interaction between photons, phonons, and electrons. (i) When the acoustic phonon scattering is dominant, ~ increases with decreasing the film thickness for phonons polarized parallel or perpendicular to the layer plane. It is also shown that ~t increases with decreasing photon frequency and increasing temperature for photons polarized parallel to the layer plane, while for photons polarized perpendicular to the layer plane the ct temperature-dependence is more complicated. (ii) If the piezoelectric scattering is dominant, ~ is also decreasing with increasing the film thickness for photons polarized parallel or perpendicular to the layer plane. But ct decreases with increasing temperature for photons polarized perpendicular to the layer plane. Moreover, numerical results for the parallel polarization are much smaller than those for the perpendicular polarization.

Free-carrier absorption in n-type GaAs films has been investigated for the case where the free carriers are confined in a quasi-two-dimensional semiconducting structure with a non-parabolic energy band of electrons. It is assumed that the carriers in semiconductors are scattered by acoustic phonons via firstly the deformation-potential coupling and secondly the piezoelectric coupling. Results show that the free-carrier absorption coefficient depends upon the polarization of the electromagnetic radiation relative to the direction normal to the quasi-two-dimensional structure, the film thickness, the photon frequency and the temperature of the semiconductors. The free-carrier absorption coefficient could be complex owing to the interaction of photons, phonons and conduction electrons in piezoelectric semiconductors. Firstly, when the deformation-potential coupling is dominant, the absorption coefficient increases with decreasing photon frequency and increasing temperature for the radiation field polarized parallel and perpendicular to the layer plane. It is also shown that the absorption coefficient increases with decreasing film thickness. Secondly, when the piezoelectric scattering is dominant, the absorption coefficient increases with decreasing photon frequency and decreasing film thickness for the radiation field polarized parallel and perpendicular to the layer plane. However, the absorption coefficient increases with increasing temperature for the radiation field polarized parallel to the layer plane while, for the radiation field polarized perpendicular to the layer plane, the absorption coefficient increases with decreasing temperature.

The effect of nonpolar optical phononscattering on the free‐carrier absorption in n‐type semiconductors such as germanium has been investigated quantum mechanically in quantizing magnetic fields. It is assumed that the energy band structure of electrons in semiconductors is nonparabolic and the dominant scattering mechanism for conduction electrons is of the nonpolar optical phononscattering. When the radiation is polarized parallel to a dc magnetic fieldB, the absorption coefficient appears to be of a complex value due to the interaction between the radiation field and the optical phonon field in nondegenerate semiconductors. Results show that the real part of the absorption coefficient oscillates with the magnetic field in the high‐field region, and imaginary part of the absorption coefficient appears with a few extremum points (peaks and dips) in high magnetic fields. These are different from those of the acoustic phononscattering in III–V compound semiconductors such as InSb or GaAs, in which the absorption coefficient oscillates with the magnetic field in lower magnetic fields and then increases monotonically with the field.

Free-carrier absorption in degenerate semiconductors such as n-type InSb has been investigated in quantizing magnetic fields at a very low temperature limit. It is assumed that the energy band of electrons in semiconductors is nonparabolic and the dominant scattering mechanism for electrons is the acoustic phonon scattering via the deformation potential coupling. Numerical results show that both real and imaginary parts of the absorption coefficient in degenerate semiconductors oscillate quite considerably with the magnetic field from the lower-field up to a higher-field region and some discontinuous points can be observed there. This is different from the numerical results shown in nondegenerate semiconductors.

The free-carrier absorption in n-type InSb films has been studied for quantum well structures fabricated from III–V semiconducting materials where the polar optical phonon scattering is predominant. We consider here two special cases: the electromagnetic radiation is polarized parallel to the layer plane and perpendicular to the layer plane separately. The energy band of electrons in semiconductors is assumed to be nonparabolic. Results show that when the electromagnetic radiation is polarized parallel to the layer plane, the free-carrier absorption coefficient is independent of temperature in a small quantum well region such as d

The free-carrier absorption has been studied for quantum well structures fabricated from III–V semiconductors such as n-type InSb films when the acoustic phonon scattering is dominant. The energy band of carriers in semiconductors is assumed to be nonparabolic. The scattering mechanisms of phonons with carriers in semiconductors are considered for the deformation-potential coupling and the piezoelectric coupling separately. Results show that the free-carrier absorption coefficient in n-type InSb films depend upon the polarization of the radiation field relative to the direction normal to the quantum well structures, the photon frequency, the film thickness and the temperature. It is also found that the free-carrier absorption coefficient could be complex due to the interaction of the radiation field and the photon field with carriers in semiconductors. Thus, the index of refraction of semiconducting films could be change due to this carrier-phonon-photon interaction.

A quantum theory for the free-carrier absorption of semiconductors to take into account the nonpolar optical phonon scattering in a semiconductor such as germanium has been studied for electrons in a parabolic energy band [1]. In quantizing magnetic fields, different scattering mechanisms give rise to different magnetic-field dependences of the scattering rates [2]. In the present work, we shall study the effect of nonpolar optical phonon scattering on the free-carrier absorption with a nonparabolic energy band of n-type nondegenerate semiconductors such as germanium.

Free-carrier absorption in n-type GaAs in quantizing magnetic fields has been investigated quantum mechanically. It is assumed that the energy band of electrons in semiconductors is nonparabolic and the dominant scattering mechanism for electrons is acoustic-phonon scattering via deformation-potential coupling. When the radiation field is polarized parallel to the magnetic field, the free-carrier absorption coefficient assumes a complex value due to the ac radiation and phonon fields. Our results show that the real part of the absorption coefficient and the imaginary part of the absorption coefficient oscillate with the magnetic field. However, at very low temperatures, oscillations in the imaginary part are diminished and its value decreases rapidly with increasing magnetic field.

The free‐carrier absorption in n‐type GaAs films has been investigated for quantum well structures fabricated from III–V semiconducting materials where polar optical phonon scattering is predominant. Attention is given mainly to the case where the electromagnetic radiation is polarized in the layer plane, and the processes involving both emission and absorption of polar optical phonons. The energy band of electrons in semiconductors is assumed to be nonparabolic. Results are shown that the free‐carrier absorption coefficient in n‐type GaAs films depends upon the photon frequency, the width of the quantum wells, and temperature. However, in the small quantum well region such as the width of quantum wells d

The magnetoresistance effect in bismuth has been studied at the very low temperature limit when the lattice scattering is dominant in solids. Results show that the magnetoresistance oscillates with the dc magnetic field and displays sharp, cusplike discontinuities due to the nonlinear and singular properties of the energy band structure of bismuth for the modified nonellipsoidal, nonparabolic (MNENP) model.

The Hall effect and transverse magnetoresistance in an intrinsic nondegenerate InSb have been investigated when the acoustic phonon scattering is the dominant scattering process. The energy‐band structure is assumed to be nonparabolic. Results show that Hall angle, Hall coefficient, and transverse magnetoresistance depend strongly on the dc magnetic field because of the energy‐dependent relaxation time. We have also studied the temperature dependence of the Hall effect and transverse magnetoresistance in an intrinsic nondegenerate InSb. The results show that the Hall coefficient is greatly enhanced in low temperatures, whereas the Hall angle changes very slowly with temperature.

The Hall effect and transverse magnetoresistance in the intrinsic nondegenerate semiconductors InSb and GaAs have been investigated according to the scattering processes of carriers in solids. These scattering processes include the acoustic phonon scattering, piezo-electric scattering and ionised-impurity scattering. The energy band structure of carriers is assumed to be nonparabolic. Results show that the Hall angle, the Hall coefficient, and the transverse magnetoresistance depend strongly on the DC magnetic field due to the energy-dependent relaxation time. The holes in semiconductors play a major role in the electrical transport phenomenon for the piezo-electric scattering and ionised-impurity scattering, while for the acoustic phonon scattering the conduction electrons in semiconductors play the major role in the electrical transport phenomenon. However, the numerical results for the piezo-electric scattering and ionised-impurity scattering are shown to be rather smaller than those for the acoustic phonon scattering in the intrinsic semiconductors. Therefore, the conduction electrons play a dominant role in the carrier transport phenomenon in the intrinsic semiconductors. A comparison between experimental work and theory for the Hall effect and transverse magnetoresistance in InSb has been made. The effect of nonparabolicity in InSb has also been discussed in comparison with the numerical results for the parabolic band structure.