Strained Axial Si/Ge Heteronanowire Devices: From Tunneling Transistors to Optical Sources

应变轴向硅/锗异质纳米线器件：从隧道晶体管到光源

• 批准号: 1068895
• 负责人: Alexander Zaslavsky
• 金额: $ 36万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-15 至 2016-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1068895&HistoricalAwards=false
• 关键词: Strained; Axial; Si; Ge; Heteronanowire

INTELLECTUAL MERITWe propose to study devices fabricated from sub-50 nm diameter nanowires with axial Si/Ge heterojunctions grown by the vapor-liquid-solid technique in collaboration with T. Picraux's epitaxy group at Los Alamos. Previous work has shown that sidewall strain relaxation greatly expands the available bandgap and strain engineering, allowing segments of essentially arbitrary SiGe composition to be incorporated into the axial nanowire. We plan to study the following classes of devices:i) axial Si/Ge heteronanowire tunneling transistors, which promise a combination of sharper switching together with higher tunneling currents due to bandgap and strain engineering along the nanowire combined with the gate-all-around device geometry; ii) Si/Ge double-barrier tunneling structures with high conduction and valence band barriers made possible by the relaxation of critical thickness limits in narrow heteronanowires;iii) Si/Ge/Si pn heterojunctions with lateral size confinement that promise stronger optical transitions due to narrower and pseudo-direct bandgap in the Ge region.Experimental results will be compared to numerical band structure simulations from both continuum elasticity and molecular dynamics (again, in collaboration with the Picraux group).BROADER IMPACTHeteronanowire tunneling transistors with gate-all-around geometry comprise one of the more realistic candidates for low-voltage switching compatible with silicon technology. Also, our work will provide experimental data for atomistic simulations of inhomogeneous strain at ~10 nm length scale. The Los Alamos collaboration research will have added graduate education impact due to extended student visits to Los Alamos. Undergraduates will work on sub-sections, including REU students from minority institutions (identified through the Brown MRSEC).

智力价值我们建议与洛斯阿拉莫斯的 T. Picraux 外延小组合作，研究由直径低于 50 nm 的纳米线制成的器件，该纳米线具有通过气-液-固技术生长的轴向 Si/Ge 异质结。 先前的工作表明，侧壁应变弛豫极大地扩展了可用的带隙和应变工程，允许将基本上任意的 SiGe 成分的片段合并到轴向纳米线中。 我们计划研究以下几类器件：i) 轴向 Si/Ge 异质纳米线隧道晶体管，由于沿纳米线的带隙和应变工程与全栅器件相结合，该晶体管有望将更锐利的开关与更高的隧道电流结合在一起几何学; ii) 具有高导带和价带势垒的 Si/Ge 双势垒隧道结构，通过放宽窄异质纳米线的临界厚度限制而成为可能；iii) 具有横向尺寸限制的 Si/Ge/Si pn 异质结，由于以下原因有望实现更强的光学跃迁Ge 区域中较窄且伪直接的带隙。实验结果将与连续弹性和分子动力学的数值能带结构模拟进行比较（再次与 Picraux 合作）更广泛的影响具有全栅几何结构的异质纳米线隧道晶体管是与硅技术兼容的低压开关的更现实的候选者之一。 此外，我们的工作将为约 10 nm 长度尺度的不均匀应变的原子模拟提供实验数据。由于学生对洛斯阿拉莫斯的访问时间延长，洛斯阿拉莫斯合作研究将增加研究生教育的影响。 本科生将在子部门工作，包括来自少数群体机构的 REU 学生（通过布朗 MRSEC 确定）。