Quantum dot superstructures

Wet chemical synthesis methods can produce semiconductors that consist of 100s to 10,000s of atoms – known as colloidal quantum dots. However, unlike the bulk semiconductors that we are familiar with in electronic devices, they are difficult to controllably dope with impurities. Furthermore, the nature of the size of the crystal impurities (e.g. single point or clusters) and the position (e.g. centre or near the surface) will have an impact on the properties of these crystals. We must understand the quantum effects in these crystals to advance their applications in electronic and optoelectronic devices. To produce electronic devices we will be forming assemblies of these quantum dots to form ‘super-crystals’. Super-crystals are analogous to atoms in a crystal, were the overlapping electron (hole) wave-functions form band-like structure. With close packing the carrier mobilties of >10 cm2V-1s-1 can be obtained. I propose to study novel construction methods for the doped quantum dot super-crystals and study their properties. By understanding the properties of the individual quantum dots and then subsequently how they behave as super-crystals, our vision is to develop methods that would enable low cost construction of flexible quantum dot electronic devices that could be used for field effect transistors (FETs), FET-biosensors, photovoltaics, and thermoelectrics.