Sparse-carrier devices and method of fabrication

A sparse-carrier device comprising:

• a supporting layer having a surface;
• a crystallographic facet including gallium arsenide selectively grown on the surface of the supporting layer, the crystallographic facet having an upper surface with a width and a length substantially parallel with the supporting layer;
• indium based quantum dots formed in at least one row on the upper surface of the crystallographic facet, the row extending along the length of the crystallographic facet and being at least one quantum dot wide and a plurality of quantum dots long, the number of rows of quantum dots determined by the width of the crystallographic facet;
• the crystallographic facet being selected so that the quantum dots selectively form only on the upper surface of the crystallographic facet;
• and
• the crystallographic facet being defined with a width to restrict formation of the indium based quantum dots thereon to the at least one quantum dot wide row of quantum dots.

A method of fabricating a sparse-carrier device comprising the steps of:

• providing a crystal substrate of a first material;
• forming a crystal structure on the crystal substrate, the crystal structure being formed by epitaxially growing a crystallographic facet of the first material with a width and a length;
• and
• selectively growing quantum dots of a second material in at least one row on the crystallographic facet, the at least one row extending along the length of the crystallographic facet and being at least one quantum dot wide and a plurality of quantum dots long, the number of rows of quantum dots determined by the width of the crystallographic facet.