US Patent 7217948 - Quantum ring polarizer

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In recent years much work has been done in using molecular beams to grow quantum dots on substrates. Quantum rings are a subspecies of quantum dots in which electrons are confined in ring structures grown on a substrate. This patent teaches fabrication of arrays of elongated arrays as well as newly discovered polarization properties of such arrays.

1. A semiconductor substrate comprised of a first compound semiconductor, and having a surface on which a plurality of quantum rings comprised of a second compound semiconductor different from the first compound semiconductor are provided, wherein each of said quantum rings has an elongated shape with an aspect ratio of 2 or more but 5 or less, and extends in a substantially same direction.