Single CdSe Quantum Dots Positioned in Nanostructured Heterogeneous Templates: Implications for High-Precision Nanoassembly

Colloidal quantum dots are chemically synthesized semiconductor nanocrystals with discrete electronic states, which can function as artificial atoms in many devices. In this work, we developed a multiphysical strategy for deterministic assembly of quantum dots in aqueous solution using nanostructured heterogeneous templates for future device integration. By introducing material heterogeneity in template design, we are able to modulate the local electric fields, surface energy, and topographic features at the nanoscale simultaneously. This allows us to assemble single quantum dots at the center of prefabricated nanoholes with high position precision and low nonspecific adsorption ratio. Moreover, we measured the strengths of different physical interactions and numerically studied their influences on the nanoassembly process. The results show that all the interactions are crucial here for overcoming the random nature of nanoassembly and further achieving high assembly precision.