A NEW MODEL FOR LIGHT-EMITTING STRUCTURES WITH A POROUS MATERIAL LAYER

A simplified band diagram of the porous layer structure is suggested. The porous silicon layer is mainly some apperiodic structure consistin g of large number of potential wells with various depths divided by ba rriers from silicon dioxide. The latter are penetrable for radiation a nd charge carriers generated there by light or injected into grains. A s nanocrystallites can be presented as quantum-size wells the spectrum of energetic states is quantized. In some cases sizes of nanocrystall ites are different and decrease at the move away from the single cryst al substrate. Then the porous silicon structure can be presented as a graded-bandgap one. The most effective emission in such a structure ca n be realised in the double injection conditions.