  Atomically flat semiconductor nanostructures have sharp photoluminescence
emission, short radiative lifetimes and a well-defined planar structure.
However, these nanostructures lack the optical and electronic fine-tuning that
justify extensive research in colloidal quantum dots. Here, we propose a
heterostructure based on CdS nanoplatelets with laterally grown CdSe. Samples
of two different thickness and varying ring width are synthesized by a one-pot
method during which CdSe ring width is controlled by Se precursor amount. The
CdSe dimensionality is continuously tuned from a 0D array of CdSe dots to a 1D
CdSe quantum ring and finally a 2D CdSe nanoplatelet. Sample characterization
shows that their optical properties are tunable by both structure thickness and
CdSe ring width. This continuous tunability extends the emission range of
nanoplatelet-based structures from 428 nm to 512 nm for 3 and 4 monolayers
structures.
