This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Semiconductor Quantum Wires and the Influence of Geometric Dimensionality on Quantum Confinement: Quantum-confinement effects are the dramatic changes in electronic and optical properties occurring in small semiconductor crystallites as a result of the geometric confinement of electrons and holes. When an electron-hole pair in an excited nanocrystal is squeezed into a dimension approaching the bulk exciton Bohr radius (~2-60 nm), the effective band gap of the semiconductor increases with decreas innanocrystal size. Thus, the magnitude of quantum confinement depends upon nanocrystal size and composition. But how about the nanocrystal shape? One may reasonably wonder which nanocrystal shape- the quantum well (layer), quantum wire, quantum rod (short wire), orquantum dot - should exhibit the inherently stronger quantum-confinement effects.The answer is known theoretically: 3D confinement is stronger than 2D confinement, which in turn is stronger than 1D confinement. Thus, the magnitude of quantum confinement should increase in the order wells
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