Three-dimensional confinement in the conduction band structure of InP

Strong quantum confinement in InP is observed to significantly reduce the s eparation between the direct and indirect conduction band states. The effec ts of three-dimensional confinement are investigated by tailoring the initi al separation between conduction band states using quantum dots (QDs) of di fferent sizes and hydrostatic pressure. Analyses of the QD emission spectra show that the X-1c states are lowest in energy at pressures of similar to 6 GPa, much lower than in the bulk. The transition to the X-1c states can b e explained by either a sequence of Gamma-L and L-X crossings, or by the cr ossover between strongly coupled Gamma and X states.