Riken Corporation

Li Wang

Hideki Hirayama

Tsung-Tse Lin

Ke Wang

In order to provide a QCL element operating in the near-infrared wavelength range, the present disclosure provides a quantum cascade laser elementhaving a semiconductor superlattice structure (QCL structure) sandwiched between a pair of conductive sectionsand. The semiconductor superlattice structure serves as an active region that emits electromagnetic waves. The active region has a plurality of unit structuresU that are stacked on top of each other. Each unit structure includes four well layersW-Wof a composition of AlGaN, separated from each other by barrier layersB-Bof a composition of AlGaN with 0&#x2264;x&#x3c;y&#x2264;1. Both of the conductive sections in the pair of conductive sections have a refractive index lower than that of the active region in which doped TCO inserted as a key role.

Quantum cascade laser element

To increase the maximum operating temperature of quantum cascade lasers of a terahertz region, a quantum cascade laser elementaccording to the present invention has a semiconductor superlattice structure sandwiched between a pair of electrodes, the semiconductor superlattice structure has an active regionthat emits electromagnetic waves of a frequency in a THz region under an external voltage applied through the pair of electrodes for operation, and the active regionhas plural unit structuresU, each of which is repeatedly layered over one another. Each of the unit structuresU has a double quantum well structure formed of a first well layerWand a second well layerWseparated from each other by a barrier layer, the first well layerWand the second well layerWhave compositions different from each other, and when the external voltage is not being applied, potential energy for electrons in the second well layerWis lower than that in the first well layerW

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Wako, Japan

Li Wang