Abstract
Temperature dependences of the magnetic susceptibility and heat capacity of CdSe quantum dots with size , 4.1, and 5.6 nm are compared to those of bulk CdSe to determine the size-dependent effects. With decreasing size , the following effects are observed: (i) room temperature optical absorption shows a blueshift of the band gap; (ii) room temperature x-ray diffraction show wurtzite structure but with smaller lattice constants; (iii) magnetic susceptibility changes from negative (diamagnetic) for the bulk to positive with magnitude increasing with decreasing ; and (iv) the Sommerfeld constant determined from the vs data increases. Possible explanations for these size-dependent properties are presented.
- Received 16 March 2005
DOI:https://doi.org/10.1103/PhysRevB.71.201307
©2005 American Physical Society