Fabrication of Semiconductor Quantum-wire and Quantum-box Structures with Bi-axial Strain and Their Applications to Photonic Devices

为了实现光通信用长波长半导体激光器的极低电流和高效率工作，本文研究了双轴应变量子线和量子盒结构的低损伤制备工艺，主要研究结果如下：1）采用电子束光刻技术制备了1.5μ m GaInAsP/InP压缩应变量子线激光器，和两步有机金属气相外延生长。采用CH_4/H_2混合气体的反应离子刻蚀（RIE）技术，首次实现了线宽为21 nm、周期为100 nm的双层堆叠量子线激光器。应变补偿多量子阱（MQW）结构被用作初始晶片和激光器，该激光器由堆叠的多个（5层）线状有源区（线宽为43 nm）组成 关于我们 100 nm波长范围内实现了100 μ m的激光脉冲。结果，在室温下获得了低至318 A/cm ^2的阈值电流密度，这几乎是从初始晶片获得的MQW激光器的60%。在85℃下，不仅获得了低阈值电流密度的工作，而且获得了高微分量子效率的工作。这一事实清楚地表明，在这项研究中所采用的制造工艺是有前途的，作为一种低损伤的实现方法的超细结构。3）通过使用我们的新开发的方法，我们实现了一种新型的分布反馈（DFB）激光器组成的周期性排列的双层线状有源区。结果表明，在1.55μm的发射波长下，器件的阈值电流密度为94 A/cm ~ 2（20μm宽），阈值电流密度为0.7mA（2.3μm宽的BH条），微分量子效率为23%/面。此外，上级单模性能归因于驻波轮廓和有源区的位置之间的匹配被首次澄清。少

In this work, in order to realize extremely low current and high efficiency operation of long-wavelength semiconductor lasers for optical communications, we have investigated low-damage fabrication process of bi-axially strained quantum wire and quantum-box structures.Results obtained in this research are summarized as follows.1) 1.5μm-wavelength GaInAsP/InP compressively strained quantum-wire lasers were fabricated by electron beam lithography, and 2-step organic metal vapor phase epitaxy growth. Double layered stacked quantum-wire lasers with the wire width of 21nm in the period of 100nm were realized for the first time by adopting reactive-ion-etching (RIE) with CH_4/H_2 gas mixture.2) In order to reduce non-radiative recombination centers at the etched/regrown interfaces due to a strain relaxation, strain compensated multiple-quantum-well (MQW) structure was used as an initial wafer and lasers consisting of stacked multiple (5 layered) wirelike active regions (the wire width of 43n … More m in the period of 100nm) were realized. As the result, threshold current density as low as 318A/cm^2, which is almost 60% of MQW lasers obtained from the initial wafer, was obtained at room temperature. Not only a low threshold current density operation but also high differential quantum efficiency operation were obtained up to 85℃. This fact clearly indicates that the fabrication process employed in this research is promising as a low-damage realization method of ultra-fine structures.3) By using our newly developed method, we realized a new type of distributed feedback (DFB) lasers consisting of periodically arranged double layered wirelike active regions. As the results, a record low threshold current density of 94A/cm^2 (20μm wide stripe) and a record low threshold current of 0.7mA (2.3μm wide BH stripe) as well as differential quantum efficiency of 23%/facet were achieved at an emission wavelength of 1.55μm. Moreover, superior single-mode-properties attributed to the matching between the standing wave profile and the position of the active region were clarified for the first time. Less