Photoluminescence of AlGaAs/GaAs quantum wells grown by metalorganic chemical vapor deposition

Abstract

Photoluminescence of Al_xGa_1−xAs/GaAs(x=0.54) single quantum wells grown by metal organic chemical vapor deposition has been investigated at both 75 and 4.2 K. AlGaAs/GaAs heterojunction abruptness was estimated to be within a few atomic layers by comparing the peak energy of the quantum well photoluminescence with the values calculated on the assumption that the radiative transition takes place between the n=1 electron subband and the n=1 heavy‐hole subband in the finite square potential well at 75 K. At 4.2 K, however, the peak energy shifts by several meV below the calculated energy, the cause of which may be formation of a two‐dimensional free exciton. The sharp photoluminescence line of the narrower well indicates that the fluctuation in thickness is less than one half the lattice constant. The emission peak shift to lower energy with the increase of excitation intensity may be the result of exchange interaction among carriers.