Generation of terahertz electric oscillations by ballistic quantized holeswith negative effective mass

The dispersion relation for the ground subband of quantized holes in a quan tum well (QW) of zink-blende-like semiconductors contains an extensive sect ion with negative effective mass (NEM). Under certain biases, stationary co ncentration distributions of the ballistic quantized holes in p(+)pp(+)-str uctures hold a self-organized region where holes with NEM predominate. The existence of such region causes a global instability of the entire stationa ry regime and the appearance of an oscillatory regime. We describe the depe ndence of the oscillatory regime on material and geometric parameters of th e structure and consider factors that influence the oscillation frequency. The typical frequencies for 0.1 mu m-structures are in the terahertz range (1-2 THz). The ballistic NEM-diodes have been classified as short, medium a nd long diodes depending on their oscillatory portrait. A new high-voltage region of oscillations that was not analytically predicted in early works i s revealed in the so-called medium and long diodes. The region appears side by side with the stable stationary regime at high voltages. Switching betw een oscillatory and stationary regimes is studied. We also discuss the feasibility of ballistic transport of quantized holes i n GaAs/AlAs p-QWs and substantiate a method of computer plotter of characte ristics for a description of nonstationary processes.