Control of carrier dimensionality in InAs quantum cascade lasers and its effect on laser characteristics

为了研究载流子尺寸对InAs量子级联激光器(QCL)激光特性的影响，我们在平行和垂直于量子阱(QWS)层的方向分别施加了磁场，并测量了其发射特性。当垂直于量子阱方向的磁场增大时，阈值电流密度J_(Th)减小，这很可能是由于朗道能级的形成所致。当平行于量子点的磁场增大时，斜率效率增强，而J<th>保持不变。为了研究其对太赫兹(THz)准分子激光器特性的影响，我们制作了GaAs太赫兹准分子激光器。此外，我们还观察到了氧化锌量子阱的子带间跃迁，这有望改善太赫兹准分子激光器的温度特性。

To investigate the effect of carrier dimensionality on the laser characteristics of InAs quantum cascade lasers (QCLs), we applied the magnetic field in the direction parallel and perpendicular to quantum wells (QWs) layers and measured the emission properties. When the magnetic field in the direction perpendicular to QWs was increased, the threshold current density (J_<th>) was decreased most probably due to the formation of the Landau levels. On the other hand, when the magnetic field parallel to QWs was increased, the enhancement of the slope efficiency was observed whereas J_<th> remained unchanged. Also to study its effect on the characteristics of terahertz (THz) QCLs, we fabricated the GaAs THz QCLs. In addition, we observed the intersubband transitions in ZnO QWs which is expected to improve the temperature characteristics of THz QCLs.