Results of an experimental study of short and longp-Ge(Au) samples are presented and compared qualitatively with data furnished by the one-dimensional theoretical model describing the evolution of domain instability in a two-parametric space ‘voltageV-emission coefficient β’. According to the theory, single-, double-, and multi-subdomain states and order-disorder-order transitions via intermittency have been observed in the system with increasing voltage. Three operation regimes of the system are found, depending on the region of the parametric space: ohmic, quenched (pulsing) and transit-time. In short samples, a second portion with S-switching is revealed in the current-voltage characteristic.