Size-dependent fine-structure splitting in self-organized InAs/GaAs   quantum dots
  A systematic variation of the exciton fine-structure splitting with quantum dot size in single InAs/GaAs quantum dots grown by metal-organic chemical vapor deposition is observed. The splitting increases from -80 to as much as 520 $\mu$eV with quantum dot size. A change of sign is reported for small quantum dots. Model calculations within the framework of eight-band k.p theory and the configuration interaction method were performed. Different sources for the fine-structure splitting are discussed, and piezoelectricity is pinpointed as the only effect reproducing the observed trend. 
R. Seguin, A. Schliwa, S. Rodt, K. P\"otschke, U. W. Pohl, and D.   Bimberg