Excitonic molecules trapped by quantum dots and isoelectronic impurities in many-valley semiconductors

Excitonic molecules with two to six excitons trapped by quantum dots or iso electronic impurity centers are studied theoretically and experimentally fo r the first time. Such excitonic molecules can exist only in many-valley se miconductors. A model of an excitonic molecule, valid for a large number of valleys in the conduction and valence bands, is examined. The formation ki netics of excitonic molecules is discussed. A material feature of excitonic molecules bound on quantum dots is the existence of tunneling transitions of excitons between quantum dots. (C) 1999 American Institute of Physics. [ S1063- 7826(99)02609-5].