Sonnenberg D, Küster A, Graf A, Heyn Ch, Hansen W
Institute of Applied Physics, University of Hamburg, D-20355 Hamburg, Germany.
Nanotechnology. 2014 May 30;25(21):215602. doi: 10.1088/0957-4484/25/21/215602. Epub 2014 May 2.
Strain-free, vertically coupled GaAs quantum dots (QDs) with an ultra-low density below 1 × 10(7) cm(-2) are fabricated by filling of self-assembled nanoholes with a GaAs/AlGaAs/GaAs layer sequence. The sizes of the two QDs, forming a QD pair (QDP), as well as the AlGaAs tunnel-barrier between the dots are tuned independently. We present atomic force microscopy studies of the QDP formation steps. We have performed photoluminescence studies of single QDPs with varied dot size and tunnel-barrier thickness. The data indicate non-resonant tunnelling between the dots. Furthermore, we apply the quantum confined Stark effect to tune the photoluminescence energy by up to 25 meV.
通过用GaAs/AlGaAs/GaAs层序列填充自组装纳米孔，制备出密度低于1×10⁷ cm⁻²的无应变垂直耦合砷化镓量子点（QD）。形成量子点对（QDP）的两个量子点的尺寸以及量子点之间的AlGaAs隧道势垒是独立调节的。我们展示了量子点对形成步骤的原子力显微镜研究。我们对具有不同量子点尺寸和隧道势垒厚度的单个量子点对进行了光致发光研究。数据表明量子点之间存在非共振隧穿。此外，我们应用量子限制斯塔克效应将光致发光能量调节高达25毫电子伏特。
