The principal mechanisms of Auger recombination of nonequilibrium carriers in semiconductor heterostructures with quantum wells are investigated. It is shown for the first time that there exist three fundamentally different Auger recombination mechanisms of (i) thresholdless, (ii) quasi-threshold, and (iii) threshold types. The rate of the thresholdless Auger process depends on temperature only slightly. The rate of the quasi-threshold Auger process depends on temperature exponentially. However, its threshold energy essentially varies with quantum well width and is close to zero for narrow quantum wells. It is shown that the thresholdless and the quasi-threshold Auger processes dominate in narrow quantum wells, while the threshold and the quasi-threshold processes prevail in wide quantum wells. The limiting case of a three-dimensional (3D) Auger process is reached for infinitely wide quantum wells. The critical quantum well width is found at which the quasi-threshold and threshold Auger processes merge into a single 3D Auger process. Also studied is phonon-assisted Auger recombination in quantum wells. It is shown that for narrow quantum wells the act of phonon emission becomes resonant, which in turn increases substantially the coefficient of phonon-assisted Auger recombination. Conditions are found under which the direct Auger process dominates over the phonon-assisted Auger recombination at various temperatures and quantum well widths.

The mechanism of Auger recombination in type-II heterostructures is studied theoretically. It is shown that the Auger recombination rate is a power function of temperature rather than an exponential function as in bulk materials. The feasibility of suppression of the Auger recombination process in the type-II heterostructures is demonstrated. The possibility of controlling the Auger recombination rate is shown to be very important for development of optoelectronic devices with improved characteristics.

A theory of the Stark effect in semiconductor quantum dots has been developed for the case of dominating polarization interaction of an electron and a hole with the nanocrystal surface. A shift of electron and hole quantum well levels in a nanocrystal in the interband absorption range in a uniform external electric field is determined by the quantum-confinement quadratic Stark effect. An electro-optical method is proposed, making it possible to estimate the characteristic quantum dot radius at which three-dimensional excitons can exist.

A theoretical analysis and computer simulation of the threshold current density j th and characteristic temperature T 0 of multiple quantum well lasers (MQWLs) are presented. Together with the spontaneous radiative recombination, the Auger recombination and the lateral diffusive leakage of carriers from the active region are included into the model. A first-principle calculation of the Auger recombination current is performed. It is shown that the lateral diffusive leakage current is controlled by the radiative and Auger currents. When calculating the carrier densities, the electrons in the barrier regions are properly taken into account. Redistribution of electrons over the active region is shown to increase the threshold current considerably. The dependences of j th and T 0 on temperature, number of QWs, cavity length and lateral size are discussed in detail. The effect of lattice and carrier heating on j th and T 0 is investigated and shown to be essential at high temperature.

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