Abstract
An analysis is made of the ionization of deep impurity centers induced by high-intensity terahertz radiation whose photon energies are tens of times lower than the impurity ionization energy. Under these conditions, ionization can be described as phonon-assisted tunneling in which carrier emission is accompanied by defect tunneling in configuration space and electron tunneling in the electric ...
Abstract
An analysis is made of the ionization of deep impurity centers induced by high-intensity terahertz radiation whose photon energies are tens of times lower than the impurity ionization energy. Under these conditions, ionization can be described as 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. At high intensities the ionization is caused by direct tunneling. 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 in tunneling as compared to static fields takes place. Phonon assisted tunneling in high frequency as well as static electric fields is suggested as a method for the characterization of deep impurities in semiconductors. It is shown that an analysis of the field and temperature dependences of the ionization probability allows to obtain defect parameters like tunneling times, the Huang-Rhys factor as well as the basic structure of the defect adiabatic potentials.
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