Strong quantum confinement effects in semiconductors: FeS2 nanoclusters

High quality, size-selected, nano-size clusters of FeS2 have been successfully grown inside inverse micellar cages and their optical absorption studied. Remarkable structure in the absorption spectrum is observed and large blue shifts in the absorption edge and other spectral features are observed upon crossing from the weak to strong quantum confinement regimes with decreasing cluster size. The bandgap appears to remain indirect down to the smallest cluster size studied (2 nm).