An electroluminescent structure and method of fabrication of that structure in materials which have an indirect bandgap in their bulk form. The processing steps can all be standard VLSI methods. Quantum columns, quantum wires or quantum dots may be formed, for example in an array, by masking, reactive ion etching and oxidation. Columns (20) may be formed by etching techniques and consist, for example, of p-type silicon material (14) which forms a p-n junction with an n-type silicon end portion (16). The space between the columns is filled with oxide (22) formed by oxidising the silicon columns during a column narrowing process. When the semiconductor core is sufficiently thin, quantum mechanical confinement effects raise the energy and the radiative recombination efficiency of injected carriers. Tuning the core diameters allows selection of individual or multiple wavelength emission bands. IMAGE
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