†Université Grenoble Alpes, INAC-SP2M, SINAPS, F-38000 Grenoble, France.
‡CEA, INAC-SP2M, SINAPS, F-38000 Grenoble, France.
Nano Lett. 2015 Apr 8;15(4):2429-33. doi: 10.1021/nl5048219. Epub 2015 Mar 16.
Applying tensile strain in a single germanium crystal is a very promising way to tune its bandstructure and turn it into a direct band gap semiconductor. In this work, we stress vapor-liquid-solid grown germanium nanowires along their [111] axis thanks to the strain tranfer from a silicon nitride thin film by a microfabrication process. We measure the Γ-LH direct band gap transition by photocurrent spectrometry and quantify associated strain by X-ray Laue microdiffraction on beamline BM32 at the European Synchrotron Radiation Facility. Nanowires exhibit up to 1.48% strain and an absorption threshold down to 0.73 eV, which is in good agreement with theoretical computations for the Γ-LH transition, showing that the nanowire geometry is an efficient way of applying tensile uniaxial stress along the [111] axis of a germanium crystal.
在单个锗晶体中施加拉伸应变是一种非常有前途的方法，可以调整其能带结构并将其转变为直接带隙半导体。在这项工作中，我们通过微加工工艺利用氮化硅薄膜的应变传递，沿[111]轴对汽-液-固生长的锗纳米线施加应力。我们通过光电流谱测量 Γ-LH 直接带隙跃迁，并通过在欧洲同步辐射设施的 BM32 光束线上进行 X 射线劳埃微衍射来定量关联应变。纳米线表现出高达 1.48%的应变和低至 0.73 eV 的吸收阈值，这与 Γ-LH 跃迁的理论计算非常吻合，表明纳米线几何形状是沿锗晶体[111]轴施加拉伸单轴应力的有效方法。
