Study on Room Temperature Operation of PbSrS and PbEuS 3 Mum Lasers

为了获得室温下工作的3微米激光器，研究了PbS单晶生长、PbSrS/PbS双异质结和多量子阱激光器以及与PbS衬底晶格匹配的PbCdSrS薄膜的热波外延生长。对于PbS单晶的生长，主要研究了衬底棒材料对生长的影响，生长所用的棒材料有BaF_2(111)、SiO_2玻璃、Al_2O_3(1000)和Al_2O_3(0101^-)。当采用SiO_2玻璃和Al_2O_3(0101)作为衬底棒时，可重复获得较大的单晶。对于PbSrS/PbS双异质结激光器，当有源层厚度为0.5um时，获得了最高的工作温度。在激光器中，PbSrS熔覆层与PbS有源层之间的晶格失配导致了PbS有源层的晶格应变。随着激活层厚度的增加，应变效应逐渐减弱，晶格失配导致界面位错较多。对于PbSrS/PbS多量子阱激光器，没有观察到工作温度的升高，但观察到了特征温度的升高，这表明提高工作温度是可能的。采用热波外延生长技术研究了与PbS晶格匹配的PbCdSrS薄膜，获得了高质量的薄膜。

To obtain 3 mum lasers operating at room temperature, PbS single crystal growth, PbSrS/PbS DH and MQW lasers and HWE growth of PbCdSrS films lattice matched with the PbS substrate were studied. For single crystal growth of PbS, dependence of growth on substrate rod materials were mainly studied, Therod materials used for the growth were BaF_2 (111), SiO_2 glass, Al_2O_3(1000), and Al_2O_3(0101^^-). When SiO_2 glass and Al_2O_3 (0101) were used as the substrate rod, a large single crystal was obtained reproducibly. For PbSrS/Pbs DH laser, highest operating temperature was obtained at the active layer thickness of 0.5 mum. In the laser, lattice mismatch between PbSrS cladding layer and PbS active layer resulted in lattice strain of the PbS active layer. With increasing active layer thickness, the strain effect grad ually decreased and the lattice mismatch resulted in many misfit dislocations at the interface. For PbSrS/PbS MQW laser, increase of the operating temperature was not observed, but increase of the characteristic temperature, which shows a possibility to increase the operating temperature, was observed. PbCdSrS films lattice matched with PbS was also studied using the HWE growth technique, and good quality films were obtained.