Temperature induced stress phase transition in CdTe quantum dots observed by dielectric constant and thermal diffusivity measurements

The authors measured the dielectric constant by capacitance method and the thermal diffusivity by thermal lens technique in the temperature range from 20 to 300 K for CdTe quantum dot doped borosilicate glass samples. Results show a huge difference between the thermal behavior of the pure glass matrix, without quantum dots, and of the doped glass, especially around 90 and 250 K. The authors attributed this difference to the phase transition experienced by the CdTe nanocrystals due to the high pressure exerted by the glass matrix over the CdTe quantum dots. The temperature induced stress is caused by the thermal expansion coefficient mismatch between the quantum dot and the glass matrix.(C) 2007 American Institute of Physics.