Strain-controlled atomic layer epitaxy, quantum wells and superlattices prepared thereby and uses thereof

A process of forming a quantum well structure which comprises a base-layer, a well-layer which comprises a group-III element, a group-V element and nitrogen, and a cap-layer, the process comprising:

• epitaxially growing the base-layer on a substrate;
• epitaxially growing the well-layer on the base-layer;
• and
• epitaxially growing the cap-layer on the well-layer,
• thereby forming the quantum well structure,
• wherein said epitaxially growing the well-layer comprises:
• exposing the base-layer to a precursor of a group-III element, to thereby form on the base-layer a first atomic layer which comprises the group-III element deposited thereon;
• terminating said exposing to said precursor of a group-III element;
• exposing the base-layer having said first atomic layer to a precursor of nitrogen, to thereby form the base-layer having said first atomic layer deposited thereon and said nitrogen absorbed onto said first atomic later;
• terminating said exposing to said precursor of nitrogen;
• exposing the base-layer to a precursor of a group-III element, to thereby form on the base-layer a second atomic layer which comprises the group-III element;
• terminating said exposing to said precursor of the group-III element;
• and
• exposing the base-layer having said first atomic layer, said nitrogen and said second atomic layer deposited thereon, to a precursor of a group-V element, to thereby form the well-layer.