Photoluminescence lifetimes of Si quantum wires

The photoluminescence lifetimes of Si quantum wires have been calculated within the effective-mass approximation. Direct or indirect transitions are involved depending on the confinement dimensions and the crystallographic orientation of the wires. The lifetimes of Si quantum wires with sizes in the range 1–4 nm as a function of the crystallographic orientations have been calculated. The magnitude of the lifetime is very sensitive to the structural parameters of the wires. Lifetimes varying from the order of nanoseconds to the order of milliseconds have been obtained. The results of our calculations provide further insight in the photoluminescence behavior of Si nanostructures and porous Si.