Department of Physics, McGill University, 3600 rue University, Montreal, Quebec H3A2T8, Canada.
Nano Lett. 2012 Feb 8;12(2):709-13. doi: 10.1021/nl2036222. Epub 2012 Jan 5.
We present a new charge sensing technique for the excited-state spectroscopy of individual quantum dots, which requires no patterned electrodes. An oscillating atomic force microscope cantilever is used as a movable charge sensor as well as gate to measure the single-electron tunneling between an individual self-assembled InAs quantum dot and back electrode. A set of cantilever dissipation versus bias voltage curves measured at different cantilever oscillation amplitudes forms a diagram analogous to the Coulomb diamond usually measured with transport measurements. The excited-state levels as well as the electron addition spectrum can be obtained from the diagram. In addition, a signature which can result from inelastic tunneling by phonon emission or a peak in the density of states of the electrode is also observed, which demonstrates the versatility of the technique.
我们提出了一种新的用于单个量子点激发态光谱学的电荷感应技术，该技术不需要图案化的电极。我们使用振荡原子力显微镜悬臂作为可移动的电荷传感器以及栅极，以测量单个自组装 InAs 量子点和背电极之间的单电子隧道。在不同悬臂振动幅度下测量的一组悬臂耗散与偏置电压曲线形成类似于通常使用传输测量测量的库仑菱形的图。可以从该图中获得激发态能级以及电子添加谱。此外，还观察到了可能由声子发射或电极态密度中的峰引起的非弹性隧道的特征，这证明了该技术的多功能性。
