Quantum Wire-on-Well (WoW) Cell With Long Carrier Lifetime for Efficient Carrier Transport

A quantum wire-on-well (WoW) structure, taking advantage of the layer undulation of an In- GaAs/GaAs/GaAsP superlattice grown on a vicinal substrate, was demonstrated to enhance the carrier collection from the confinement levels and extend the carrier lifetime (220 ns) by approximately 4 times as compared with a planar reference superlattice. Strained InGaAs/GaAs/GaAsP superlattices were grown on GaAs substrates under exactly the same condition except for the substrate misorientation (0o- and 6o- off). The growth on a 6o-off substrate induced significant layer undulation as a result of step bunching and non-uniform precursor incorporation between steps and terraces whereas the growth on a substrate without miscut resulted in planar layers. The undulation was the most significant for InGaAs layers, forming periodically aligned InGaAs nanowires on planar wells, a wire-on-well structure. As for the photocurrent corresponding to the sub-bandgap range of GaAs, the light absorption by the WoW was extended to longer wavelengths and weakened as compared with the planar superlattice, and almost the same photocurrent was obtained for both the WoW and the planar superlattice. Open-circuit voltage for the WoW was not affected by the longer-wavelength absorption edge and the same value was obtained for the two structures. Furthermore, the superior carrier collection in the WoW, especially under forward biases, improved fill factor compared with the planer superlattice

Quantum wire-on-well (WoW) cell with long carrier lifetime for efficient carrier transport

A quantum wire-on-well (WoW) structure, taking advantage of the layer undulation of an InGaAs/GaAs/GaAsP superlattice grown on a vicinal substrate, was demonstrated to enhance the carrier collection from the confinement levels and extend the carrier lifetime (220 ns) by approximately four times more than a planar reference superlattice. Strained InGaAs/GaAs/GaAsP superlattices were grown on GaAs substrates under exactly the same conditions except for the substrate misorientation (0 and 6 ° off). The growth on a 6 ° off substrate induced significant layer undulation as a result of step bunching and non-uniform precursor incorporation between steps and terraces, whereas the growth on a substrate without miscut resulted in planar layers. The undulation was the most significant for InGaAs layers, forming periodically aligned InGaAs nanowires on planar wells, a WoW structure. As for the photocurrent corresponding to the sub-bandgap range of GaAs, the light absorption by the WoW was extended to longer wavelengths and weakened as compared with the planar superlattice. Almost the same photocurrent was obtained for both the WoW and the planar superlattice. Open-circuit voltage for the WoW was not affected by the longer-wavelength absorption edge, and the same value was obtained for the two structures. Furthermore, the superior carrier collection in the WoW, especially under forward biases, improved fill factor compared with the planer superlattice

Silicon Photonics beyond Optical Interconnects

In this paper we present the use of a 300mm Si-Photonic platform for applications beyond the data communication. Beam steering and beam shaping for free-space-optics and hybrid III-V/ Si optical switch for computing applications are discussed