FAR INFRARED STUDY OF SHALLOW ACCEPTORS IN GAAS/ALGAAS QUANTUM WELLS.

Far infrared transmission has been used to study beryllium acceptors doped in the center of GaAs/AlGaAs quantum wells and bulk GaAs. From the infrared measurements a binding energy of 28. 5 meV was inferred, in agreement with photoluminescence measurements. The effects of confinement are evident in shifts to progressively higher frequencies of the dominant transitions as the well width is decreased from 200 angstrom to 100 angstrom. The magnetic-field dependence of the observed transitions has been investigated between 0 and 9. 0 T at temperatures between 4. 2 and 30 K for the bulk sample and a 200-angstrom-well-width sample. The shifts of the transitions with magnetic field are much smaller than predicted by recent calculations for confined acceptors.