Exciton Binding Energy in Extremely Shallow Quantum Wells
J. Kossut
Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warszawa, Poland

and J.K. Furdyna
Department of Physics, University of Notre Dame, Notre Dame, IN 46556, USA
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The usual approach to the problem of excitons in semiconductor quan­tum wells is to assume that both the electron or the hole are primarily localized in the potential well regions defined by the band offsets, i.e., that the quantum wells are deep. We re-examine the problem of the exciton in the presence of a very shallow square well potential due to the (small) conduc­tion and valence band offsets in a semiconducting heterostructure. We show that the combined effects of the shallow well and the Coulomb interaction between the electron and the hole are equivalent to an effective potential acting on the center-of-mass of a three-dimensional exciton. We calculate the shape of such a potential and show it to be satisfactorily approximated by the potential of a parabolic well.
DOI: 10.12693/APhysPolA.87.528
PACS numbers: 73.20.Dx, 71.36.+c, 73.61.Ga