SENSITIVITY OF WAVE-FUNCTION ENVELOPES UPON INTERFACE POSITION - SEMICONDUCTOR-INSULATOR BOUNDARY

Exact wave functions for a particle in a quantum well with infinite co nduction-band offset are calculated for a well material described by t he Kronig-Penney model. The exact wave-function envelopes are extremel y sensitive to the position of the interfaces within certain ''boundar y-sensitive domains.'' At certain ''critical positions'' for the inter face within these domains the envelopes fulfill zero-slope boundary co nditions. In the nth band there are normally n well defined boundary-s ensitive domains. However, for narrow-gap materials the boundary-sensi tive domains become wider and may fill the entire unit cell. In each b and, effective-mass theory reproduces adequately the low-lying energy eigenvalues but not the wave-function envelopes, and may give misleadi ng results for oscillator strengths.