Huang Minghuang, Ritz Clark S, Novakovic Bozidar, Yu Decai, Zhang Yu, Flack Frank, Savage Donald E, Evans Paul G, Knezevic Irena, Liu Feng, Lagally Max G
Department of Materials Science and Engineering, University of Wisconsin, Madison, Wisconsin 53706, USA.
ACS Nano. 2009 Mar 24;3(3):721-7. doi: 10.1021/nn8008883.
Significant new mechanical and electronic phenomena can arise in single-crystal semiconductors when their thickness reaches nanometer dimensions, where the two surfaces of the crystal are physically close enough to each other that what happens at one surface influences what happens at the other. We show experimentally that, in silicon nanomembranes, through-membrane elastic interactions cause the double-sided ordering of epitaxially grown nanostressors that locally and periodically highly strains the membrane, leading to a strain lattice. Because strain influences band structure, we create a periodic band gap modulation, up to 20% of the band gap, effectively an electronic superlattice. Our calculations demonstrate that discrete minibands can form in the potential wells of an electronic superlattice generated by Ge nanostressors on a sufficiently thin Si(001) nanomembrane at the temperature of 77 K. We predict that it is possible to observe discrete minibands in Si nanoribbons at room temperature if nanostressors of a different material are grown.
当单晶半导体的厚度达到纳米尺寸时，会出现显著的新机械和电子现象，此时晶体的两个表面在物理上足够接近，以至于一个表面发生的事情会影响另一个表面发生的事情。我们通过实验表明，在硅纳米膜中，跨膜弹性相互作用导致外延生长的纳米应力器的双面有序排列，这些应力器会局部且周期性地使膜产生高度应变，从而形成应变晶格。由于应变会影响能带结构，我们创建了高达带隙20%的周期性带隙调制，实际上形成了一个电子超晶格。我们的计算表明，在77K温度下，由足够薄的Si(001)纳米膜上的Ge纳米应力器产生的电子超晶格的势阱中可以形成离散的微带。我们预测，如果生长不同材料的纳米应力器，有可能在室温下在硅纳米带中观察到离散的微带。
