Hyperboloid-drum structures and method of fabrication of the same using ion beam etching

A hyperboloid-drum element comprising

• an active region having a quantum well structure;
• an n-type barrier layer and a p-type barrier layer respectively formed on both surfaces of the active region;
• an n-type distributed Bragg reflector (DBR) placed outside of the n-type barrier layer;
• and
• a p-type distributed Bragg reflector (DBR) placed outside of the p-type barrier layer;
• wherein the diameter of the hyperboloid-drum element decreases gradually away from each of the distributed Bragg reflectors and toward the active region such that a minimum diameter occurs at the active region where a quantum dot is positioned.

A fabrication method of a hyperboloid-drum element, comprising:

• forming an epitaxial layer having an active region on a substrate, and
• etching the epitaxial layer into a shape of the hyperboloid-drum having a minimum diameter at the active region by an ion-beam etching method,
• wherein forming the epitaxial layer comprises:
• forming an n-type distributed Bragg reflector on an n+ doped substrate;
• forming an n-type barrier layer on top of the n-type distributed Bragg reflector;
• forming an active region with a quantum well on top of the n-type barrier layer;
• forming a p-type barrier layer on top of the active region;
• and
• forming a p-type distributed Bragg reflector on top of the p-type barrier layer.