Studies on Semiconductor Quantum Wells and Long-Wavelength Infrared Lasers

我们研究了用于带间中红外激光器的IV-VI半导体薄膜和量子阱，以及用于子带间量子级联激光器的AlGaN基量子阱。在IV-VI半导体中，我们制备了3-4μm区的PbSrS/PbS激光器和4-6μm区的PbCaTe/PbTe激光器，并在PbCaTe/PbTe多量子阱激光器上获得了235K的脉冲激光运转。我们还研究了PbSnCaTe薄膜和PbSnCaTe/PbSnTe超晶格在6-20μm附近的长波长激光应用。异质结变成了I型，这对有效限制PbSnTe有源层中的电子和空穴是有利的。在用于子带间激光应用的AlGaN系统中，我们采用热壁外延的方法制备了高质量的AlGaN基薄膜和超晶格。我们提出了由一个原子层AlN和大约10个GaN原子层组成的(AlN)_1/(GaN)_n短周期超晶格用于中红外亚带间激光器，并提出了[(AlN)_1/(GaN)_&lt；n1&gt；]_m/(AlN)_&lt；n2&gt；量子级联结构，它利用AlN/GaN中的大偏振场将电子注入到更高的子带。我们用热壁外延方法制备了短周期超晶格和量子级联结构，X射线衍射和透射电子显微镜测量证实了结构的可控性。

We studied IV-VI semiconductor films and quantum wells for interband mid-infrared laser applications, and AlGaN-based quantum wells for intersubband quantum-cascade laser applications. In IV-VI semiconductors, we prepared PbSrS/PbS lasers for 3-4μm region and PbCaTe/PbTe lasers for 4-6μm region, and obtained pulsed laser operation up to 235K in the PbCaTe/PbTe MQW laser. We also studied PbSnCaTe films and PbSnCaTe/PbSnTe superlattices for longer wavelength laser applications around 6-20μm. The heterojunction becomes type-I which is useful for effective confinements of electrons and holes in the PbSnTe active layer. In the AlGaN system for intersubband laser applications, we prepared high quality AlGaN based films and superlattices by hot wall epitaxy. We proposed (AlN)_1/(GaN)_n short-period superlattices consisting of one atomic layer AlN and around 10 atomic layers of GaN for mid-infrared intersubband lasers, and also proposed [(AlN)_1/(GaN)_<n1>]_m/(AlN)_<n2> quantum cascade structures which utilize large polarization fields in the AlN/GaN to inject electrons into higher subbands. We prepared the short-period superlattices and the quantum-cascade structures by hot wall epitaxy and well-controlled structures were confirmed by X-ray diffraction and TEM measurements.