QUANTUM-CASCADE LASER ELEMENT AND QUANTUM-CASCADE LASER DEVICE

摘要

This quantum-cascade laser element is provided with: a semiconductor substrate; a semiconductor stack formed on the semiconductor substrate so as to have a ridge portion comprising an active layer having a quantum-cascade structure; an embedded layer including a first part formed on a side surface of the ridge portion and a second part extending from an edge portion of the first part on the semiconductor substrate side along the width direction of the semiconductor substrate; and a metal layer formed at least on a top surface of the ridge portion and on the first part. In the thickness direction of the semiconductor substrate, a surface of the second part opposite to the semiconductor substrate is positioned between a surface of the active layer opposite to the semiconductor substrate and a surface of the active layer on the semiconductor substrate side. When viewed from the width direction of the semiconductor substrate, a part of the metal layer on the first part overlaps the active layer. The metal layer is formed directly on the first part.