Radiative recombination and impact ionization in semiconductor nanostructures (review)

The processes of radiative recombination and impact ionization in light-emitting structures based on bulk semiconductors, heterostructures with high potential barriers, nanostructures with deep quantum wells, and nanocrystals with quantum dots are reviewed. It is shown that enhancement of the quantum efficiency and luminescence optical power in all the investigated structures is caused by a common physical mechanism, specifically, the creation of additional electron–hole pairs during impact ionization by hot carriers heated at the high band offset at the heterointerface under current pumping or by the multiplication of carriers in nanocrystals upon multiexciton generation under illumination by high-energy photons.