| 主权项 |
1. A semiconductor stack comprising: a semiconductor DBR (Distributed Bragg Reflector) formed on a substrate; and a resonator formed on the semiconductor DBR, formed by laminating wide-band semiconductor layers and active layers alternately, wherein a band gap of the wide-band semiconductor layers is greater than that of the active layers, wherein each of the active layers includes MQWs (Multiple Quantum Wells) and two spacer layers formed one on each surface of the MQWs, wherein the MQWs are formed by laminating barrier layers and quantum well layers alternately, wherein n layers of the wide-band semiconductor layers are formed, and a band gap Egm of an m-th wide-band semiconductor layer counting from the substrate and a band gap Egm-1 of an m−1-th wide-band semiconductor layer counting from the substrate satisfy Egm-1<Egm where n and m are integers greater than or equal to 3, and 1<m≦n, wherein each of a first to an n−1-th wide-band semiconductor layers counting from the substrate has its center positioned at a node of a standing wave, wherein an n-th wide-band semiconductor layer counting from the substrate has one of its surface attached to the active layer positioned at a node of the standing wave, and another of its surface positioned at an antinode of the standing wave. |
