THEORETICAL-STUDY OF SHALLOW ACCEPTOR STATES UNDER THE INFLUENCE OF BOTH A CONFINEMENT POTENTIAL AND A DEFORMATION POTENTIAL

Energy levels of the ground and the excited shallow acceptor states ha ve been calculated for center-doped strain-free GaAs/AlxGa1-xAs quantu m wells (QW's) in the presence of an external pressure and in strained InxGa1-xAs/AlyGa1-yAs QW's. The impurity states are calculated using a four-band effective-mass theory, in which the valence-band mixing as well as the mismatch of the band parameters and the dielectric consta nts between well and barrier materials have been taken into account. T he acceptor binding energies and the internal electronic transitions a re calculated. The results show that an applied external pressure in G aAs/AlxGa1-xAs QW's or built-in strain in InxGa1-xAs/AlyGa1-yAs QW's s trongly influences the acceptor states. The oscillator strengths betwe en the acceptor ground states and the different excited p-like states are also calculated for the InxGa1-xAs/Al0.3Ga0.7As system with three different indium fractions x. The results show clearly that a built-in strain strongly influences the transition energies and the relative o scillator strengths.