1. Colloidal nanomaterials

Until the 1960s, low-dimensional objects remained the preserve of theorists. In the 1970s, with advances in fabrication methods and in particular molecular jet epitaxy, it became possible to design samples whose size is smaller than the Bohr radius of the material of which they are made. While silicon is the king of electronics, its indirect gap makes it a poor candidate for optical applications. In contrast, III-V semiconductors, and GaAs in particular, feature a band structure with a direct band gap (i.e. the conduction band maximum is located at the same pulse as the conduction band minimum), so it's only natural that these materials should be used for optoelectronics. In nanoscale semiconductor structures, the bandgap energy is modified relative to bulk material by quantum confinement. Quantum confinement has enabled a paradigm...