High pressure photoluminescence of CdZnSe quantum dots: Alloying effect

The pressure dependence of photoluminescence of wurtzite 5.5 nm CdZnSe alloy quantum dots (QDs) was studied and compared with that of the wurtzite 3.5 nm CdSe QDs. The direct Gamma energy gaps of wurtzite QDs were found to increase with the pressure, and the pressure coefficients were gained as 35.4 meV/GPa for CdZnSe and 28.4 meV/GPa for CdSe QDs. The authors attributed the high value of pressure coefficient for CdZnSe alloy QDs to the alloying effect with strengthening the anion-cation s-s orbital coupling and weakening p-d orbital coupling in the alloy. The result demonstrates that the alloying process has a dominant role in the electronic state and structure transition under high pressure. (C) 2007 American Institute of Physics.