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For slow recombination waves in Si:Zn, stationary intensity profiles along the specimen are measured with an SEM operated in the voltage-contrast mode. The main findings are as follows: (i) The intensity falls from a maximum with increasing distance from the cathode, where a stationary high-field domain is located, and almost vanishes far short of the anode. (ii) The intensity grows with specimen voltage. (iii) The voltage-contrast image for the highest specimen voltage displays oscillatory potential variation over the stationary high-field domain, indicating the stratification of electric field. [ABSTRACT FROM AUTHOR]

For slow recombination waves in Si:Zn, stationary intensity profiles along the specimen are measured with an SEM operated in the voltage-contrast mode. The main findings are as follows: (i) The intensity falls from a maximum with increasing distance from the cathode, where a stationary high-field domain is located, and almost vanishes far short of the anode. (ii) The intensity grows with specimen voltage. (iii) The voltage-contrast image for the highest specimen voltage displays oscillatory potential variation over the stationary high-field domain, indicating the stratification of electric field. [ABSTRACT FROM AUTHOR]

A nonlinear theory of recombination waves in semiconductors is constructed that addresses quasi-neutrality breaking in the electron–hole plasma with fully developed instability. It is established that with increasing applied electric field a recombination wave of uniform amplitude is transformed into a traveling solitary domain; the domain formation manifests itself in the transition from almost sinusoidal to relaxation oscillations of current. A formula is derived that relates the domain velocity to the properties of the material and the current–voltage characteristic of the specimen. The predicted transformation of recombination waves is verified by checking against previously obtained experimental results concerning slow recombination waves in Si specimens with Zn doping compensation. It is found that a calculated field at which relaxation oscillations arise agrees with the measured one. The frequency of relaxation oscillations is examined as a function of applied field on the basis of the theory and the experiment. The calculated characteristic is shown to be in qualitative and quantitative agreement with the measured one. [ABSTRACT FROM AUTHOR]

The generation and voltage dependence of a stationary high-field domain in Si : Zn about the excitation threshold of slow recombination waves are investigated by scanning electron microscopy. It is found that the domain arises at the cathode when the electric field in the specimen is about 10 V/cm. The field inside the domain and at its boundary (~103 V/cm) considerably exceeds the average specimen field. The field in the domain linearly increases with dc specimen voltage but stays within the same order of magnitude. The domain linearly grows to approximately 100 μm with increasing dc specimen voltage. Domain generation is found to occur in passing from a linear to a sublinear portion of the specimen current–voltage characteristic. [ABSTRACT FROM AUTHOR]