ABSTRACT
Semiconductor quantum dots (QDs) are a fascinating nanomaterial that goes much beyond its proclaimed properties of size-tunable light emission. Not only the size but also the composition of the bulk semiconductor crystal used to make the QDs modify all their optical properties. Indeed, modifying the composition of the bulk semiconductor means that it is no longer the same material and obviously results in different material characteristics affecting the bandgap among others. With technological advances allowing the preparation of crystalline materials at the nanometer scale with a limited number of atoms, typically between 1,000 and 10,000 in QDs, it is now common knowledge that material properties are independent of size only down to a minimum threshold. Below that minimum, the size dependence is illustrated in Figure 19.1 specifically for the optical property of the light emitted by the QDs under ultraviolet (UV) or visible (Vis) excitation: the emission can be tuned to shorter wavelengths with decreasing QD size, as represented by the colored arrows.
