Lehrstuhl für Experimentalphysik 1 and Augsburg Centre for Innovative Technologies (ACIT), Universität Augsburg , Universitätsstraße 1, 86159 Augsburg, Germany.
Nano Lett. 2014 May 14;14(5):2256-64. doi: 10.1021/nl4040434. Epub 2014 Apr 3.
We probe and control the optical properties of emission centers forming in radial heterostructure GaAs-Al0.3Ga0.7As nanowires and show that these emitters, located in Al0.3Ga0.7As layers, can exhibit quantum-dot like characteristics. We employ a radio frequency surface acoustic wave to dynamically control their emission energy, and occupancy state on a nanosecond time scale. In the spectral oscillations, we identify unambiguous signatures arising from both the mechanical and electrical component of the surface acoustic wave. In addition, different emission lines of a single emission center exhibit pronounced anticorrelated intensity oscillations during the acoustic cycle. These arise from a dynamically triggered carrier extraction out of the emission center to a continuum in the radial heterostructure. Using finite element modeling and Wentzel-Kramers-Brillouin theory we identify quantum tunneling as the underlying mechanism. These simulation results quantitatively reproduce the observed switching and show that in our systems these emission centers are spatially separated from the continuum by >10.5 nm.
我们探测和控制在径向异质结构 GaAs-Al0.3Ga0.7As 纳米线中形成的发射中心的光学性质，并表明这些位于 Al0.3Ga0.7As 层中的发射器可以表现出类似量子点的特性。我们采用射频表面声波在纳秒时间尺度上动态控制它们的发射能量和占据态。在光谱振荡中，我们确定了来自表面声波的机械和电气分量的明确特征。此外，单个发射中心的不同发射线在声循环中表现出明显的反相关强度振荡。这是由于载流子从发射中心动态提取到径向异质结构中的连续体中。使用有限元建模和 Wentzel-Kramers-Brillouin 理论，我们确定量子隧穿是潜在的机制。这些模拟结果定量地再现了观察到的开关，并表明在我们的系统中，这些发射中心与连续体的空间分离>10.5nm。
