Collaborative Research: Quantum-Cascade-Laser Active Materials Based on Silicon-Germanium Nanomembranes

合作研究：基于硅锗纳米膜的量子级联激光活性材料

• 批准号: 0907296
• 负责人: Roberto Paiella
• 金额: $ 23.49万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0907296&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantum; Cascade; Laser

Technical. This project addresses synthesis/processing/fabrication research to explore quantum-cascade (QC) mid- and far-infrared light-emitting materials based on SiGe quantum wells (QWs). Since QC lasers are semiconductor light sources based on intersubband (ISB) transitions (i.e., electronic transitions between quantized states within the same energy band), their operation is essentially unaffected by the nature of the energy band gap of the underlying materials. Hence such considerations provide an approach for the demonstration of laser action in silicon ? a goal complicated by the indirect band gap of (Si)(Ge). Strain, however, associated with Si/SiGe QWs appears as a significant challenge to progress. This project takes a new approach, in which elasti-cally relaxed SiGe nanomembranes are used as the growth substrates and/or the active material. Such nanomembranes will be grown epitaxially on Si(Ge)-on-insulator substrates and then re-leased from the handle wafer by removing the underlying oxide layer via wet etching. The de-sired result would be a free-standing heterostructure where strain relaxation occurs via elastic strain sharing among the constituent epilayers without the formation of defects, and thus be vir-tually free of dislocations. The released nanomembranes could then be transferred onto other substrates. Further challenges complicating the demonstration of silicon-based QC lasers are provided by design issues specific to the SiGe QW materials system, which are also being ad-dressed on this project. An approach based on electronic ISB transitions in the L valleys of Ge/SiGe QWs will be explored. Recent calculations indicate that this approach may have advan-tages over the p-type structures that have been investigated so far, including longer nonradiative lifetimes, larger oscillator strengths, and more efficient tunneling transport.Non-Technical. The project addresses fundamental research issues in a topical area of elec-tronic/photonic materials science having technological relevance. The proposed use of nanomembrane technology for the fabrication of complex semiconductor quantum structures has the potential for broad technological impact beyond the SiGe materials system and the QC-laser device application described above. Moreover, the project activities will promote education through the training of students across disciplines, ranging from semiconductor epitaxial growth to nanomembrane synthesis and processing, bandgap engineering, and THz (terahertz) photonics. To increase the effectiveness and scope of the program, the involvement of undergraduates and high-school interns will be emphasized, by leveraging existing programs with a strong focus on under-represented minorities.

技术的。该项目介绍了基于SIGE Quantum Wells（QWS）的量子cascade（QC）中和远红外发光材料的合成/加工/制造研究。由于QC激光器是基于间隔（ISB）过渡的半导体光源（即，在同一能量带中的量化状态之间的电子过渡），因此它们的运行本质上不受基础材料的能带隙的性质影响。因此，这种考虑为硅中激光作用的演示提供了一种方法？ （SI）（GE）的间接带隙使目标复杂化。但是，与Si/Sige QWS相关的应变似乎是进步的重大挑战。该项目采用了一种新的方法，其中将弹性弛豫的SIGE纳米膜用作生长底物和/或活性材料。这种纳米膜将在SI（GE） - 在 - 隔离剂底物上外上植物生长，然后通过通过湿蚀刻去除下面的氧化物层从手柄晶片中重新租用。去缝制的结果将是一个独立的异质结构，其中应变松弛通过弹性应变在没有缺陷的形成而不形成的组成型表层之间发生，从而无处不在脱位。然后可以将释放的纳米膜转移到其他底物上。 Sige QW材料系统的设计问题提供了进一步的挑战，使基于硅的QC激光器的演示复杂化，这些问题也在该项目上受到广泛关注。将探索基于GE/SIGE QWS L谷中电子ISB转换的方法。最近的计算表明，这种方法可能对迄今已研究的P型结构具有优势，包括较长的非生育寿命，较大的振荡器强度和更有效的隧道运输。该项目解决了具有技术相关性的Elec-tronic/Photonic材料科学的主题领域的基本研究问题。纳米膜技术用于制造复杂半导体量子结构的拟议使用可能会产生超出SIGE材料系统和上述QC-LASER设备应用程序的广泛技术影响。此外，项目活动将通过跨学科的学生培训学生，从半导体的外在增长到纳米膜合成和加工，带隙工程以及THZ（Terahertz）光子学。为了提高该计划的有效性和范围，将通过利用现有计划的重点是代表性不足的少数群体来强调本科生和高中实习生的参与。