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Excitation of Deep Defects by Intense Terahertz Radiation

100%

Ganichev S.

An analysis is done of the ionization of deep impurity centers by high-intensity terahertz radiation, with photon energies tens of times lower than the impurity ionization energy. Under these conditions, ionization can be described as direct tunneling and phonon-assisted tunneling in which carrier emission is accompanied by defect tunneling in configuration space and electron tunneling in the electric field of the radiation. Within a broad range of intensity, frequency, and temperature, the terahertz electric field of the radiation acts like a static field. For very high frequencies and low temperatures an enhancement of tunneling as compared to static fields was observed. The transition between the quasi-static and the high frequency regime is determined by the tunneling time. For the case of deep impurities this is the time of redistribution of the defect vibrational system which depends strongly on temperature and the impurity structure.

Terahertz Radiation Induced Spin Photocurrents in Non-Magnetic Low Dimensional Structures

63%

Ganichev S., Prettl W.

Acta Physica Polonica A

2005

vol. 108

issue 4

581-608

Spin photocurrents generated by homogeneous excitation with terahertz radiation in low dimensional structures are reviewed. Three microscopic mechanisms are responsible for the occurrence of an electric current linked to a uniform spin polarization in a quantum well, the circular photogalvanic effect, the spin-galvanic effect and the magneto-gyrotropic effect. These phenomena provide several methods to investigate various spin properties in low dimensional structures like details of band structure and spin relaxation time.

Terahertz Luminescence and Absorption under Impurity Breakdown in Quantum Wells and Strained Semiconductor Layers

27%

Vorobjev L., Firsov D., Shalygin V., Panevin V., Sofronov A., Ustinov V., Zhukov A., Egorov A., Andrianov A., Zakhar'in A., Ganichev S., Danilov S., Kozlov D.

Acta Physica Polonica A

2008

vol. 113

issue 3

925-928

We present the results of THz luminescence investigations in structures with Si-doped quantum wells and Be-doped GaAsN layers under strong lateral electric field. The peculiar property of these structures is the presence of resonant impurity states which arise due to dimensional quantization in quantum wells and due to built-in strain in GaAsN epilayers. The experimentally obtained THz emission spectra consist of the lines attributed to intra-center electron transitions between resonant and localized impurity states and to the electron transitions involving the subband states. Absorption of THz radiation and its temperature dependence was also studied in structure with tunnel-coupled quantum wells at equilibrium conditions and under electric field.

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3 Acta Physica Polonica A

1 2008

1 2005

1 1999

3 Ganichev S.

1 Andrianov A.

1 Danilov S.

1 Egorov A.

1 Firsov D.

1 Kozlov D.

1 Panevin V.

1 Prettl W.

1 Shalygin V.

1 Sofronov A.

1 Ustinov V.

1 Vorobjev L.

1 Zakhar'in A.

1 Zhukov A.

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Excitation of Deep Defects by Intense Terahertz Radiation

Terahertz Radiation Induced Spin Photocurrents in Non-Magnetic Low Dimensional Structures

Terahertz Luminescence and Absorption under Impurity Breakdown in Quantum Wells and Strained Semiconductor Layers