IBM Research-Zurich, Säumerstrasse 4, 8803 Rüschlikon, Switzerland.
Nano Lett. 2013 Mar 13;13(3):917-24. doi: 10.1021/nl303694c. Epub 2013 Feb 18.
Strain engineering has been used to increase the charge carrier mobility of complementary metal-oxide-semiconductor transistors as well as to boost and tune the performance of optoelectronic devices, enabling wavelength tuning, polarization selectivity and suppression of temperature drifts. Semiconducting nanowires benefit from enhanced mechanical properties, such as increased yield strength, that turn out to be beneficial to amplify strain effects. Here we use photoluminescence (PL) to study the effect of uniaxial stress on the electronic properties of GaAs/Al0.3Ga0.7As/GaAs core/shell nanowires. Both compressive and tensile mechanical stress were applied continuously and reversibly to the nanowire, resulting in a remarkable decrease of the bandgap of up to 296 meV at 3.5% of strain. Raman spectra were measured and analyzed to determine the axial strain in the nanowire and the Poisson ratio in the <111> direction. In both PL and Raman spectra, we observe fingerprints of symmetry breaking due to anisotropic deformation of the nanowire. The shifts observed in the PL and Raman spectra are well described by bulk deformation potentials for band structure and phonon energies. The fact that exceptionally high elastic strain can be applied to semiconducting nanowires makes them ideally suited for novel device applications that require a tuning of the band structure over a broad range.
应变工程被用于提高互补金属氧化物半导体晶体管的电荷载流子迁移率，以及增强和调整光电设备的性能，实现波长调谐、偏振选择性和抑制温度漂移。半导体纳米线受益于增强的机械性能，例如增加的屈服强度，这有利于放大应变效应。在这里，我们使用光致发光 (PL) 来研究单轴应力对 GaAs/Al0.3Ga0.7As/GaAs 核/壳纳米线电子特性的影响。连续且可逆地对纳米线施加压缩和拉伸机械应力，导致带隙显著减小，在 3.5%的应变量下可达 296 meV。测量和分析拉曼光谱以确定纳米线中的轴向应变和 <111> 方向的泊松比。在 PL 和拉曼光谱中，我们观察到由于纳米线各向异性变形而导致的对称破缺的指纹。在 PL 和拉曼光谱中观察到的位移很好地描述了能带结构和声子能量的体变形势。可以向半导体纳米线施加异常高的弹性应变的事实，使得它们非常适合需要在宽范围内调整能带结构的新型器件应用。
