Abstract:
In the case of semiconductors with an indirect energy gaps of interdicted zones of the type ZnP2 (D84) optical transition with absorption and emission of phonons are found in the free exiton zone. In the case of alloyed crystals those materials in a small mixture appear impurity states on which the bound exitons are located. With the contribution of bound exitons also happens the indirect transition with absorption and emission of phonons. This type of transition is found and is also examined in others semiconductors, as well as in crystals of GaP. The indirect transitions with absorption and emission of phonons can take place in the same time with the contribution of the same photons, in free exiton zone as well as the bound exciton zone. In this case collision and even the interference of absorption combined with the processes mentioned above take place.