Comment on ``Two-dimensional charged-biexciton complexes''
  We re-examine the results of A. Thilagam [Phys. Rev. B 55, 7804 (1997)], who calculated the ratio of the binding energies of the two dimensional exciton complexes. We point out that, for charged biexciton complexes, this calculation is oversimplified, and these systems do not always form bound states if they interact via pure Coulomb interaction. If experiment proved the existence of these objects, their bindings would have to be explained by other mechanisms. 
K. Varga