Thomas Frederick S, Baumgartner Andreas, Gubser Lukas, Jünger Christian, Fülöp Gergő, Nilsson Malin, Rossi Francesca, Zannier Valentina, Sorba Lucia, Schönenberger Christian
Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056 Basel, Switzerland.
Nanotechnology. 2019 Nov 28;31(13):135003. doi: 10.1088/1361-6528/ab5ce6.
We present a comprehensive electrical characterization of an InAs/InP nanowire (NW) heterostructure, comprising of two InP barriers forming a quantum dot (QD), two adjacent lead segments and two metallic contacts. We demonstrate how to extract valuable quantitative information of the QD. The QD shows very regular Coulomb blockade resonances over a large gate voltage range. By analyzing the resonance line shapes, we map the evolution of the tunnel couplings from the few to the many electron regime, with electrically tunable tunnel couplings from <1 μeV to >600 μeV, and a transition from the temperature to the lifetime broadened regime. The InP segments form tunnel barriers with almost fully symmetric tunnel couplings and a barrier height of ∼350 meV. All of these findings can be understood in great detail based on the deterministic material composition and geometry. Our results demonstrate that integrated InAs/InP QDs provide a promising platform for electron tunneling spectroscopy in InAs NWs, which can readily be contacted by a variety of superconducting materials to investigate subgap states in proximitized NW regions, or be used to characterize thermoelectric nanoscale devices in the quantum regime.
我们展示了对一种由两个形成量子点（QD）的磷化铟（InP）势垒、两个相邻的引线段和两个金属接触组成的砷化铟/磷化铟（InAs/InP）纳米线（NW）异质结构的全面电学表征。我们演示了如何提取量子点的有价值的定量信息。该量子点在较大的栅极电压范围内显示出非常规则的库仑阻塞共振。通过分析共振线形状，我们描绘了从少电子到多电子区域隧道耦合的演变，其电可调隧道耦合范围从<1微电子伏特到>600微电子伏特，并且存在从温度展宽到寿命展宽区域的转变。磷化铟段形成具有几乎完全对称隧道耦合和~350毫电子伏特势垒高度的隧道势垒。基于确定性的材料组成和几何结构，可以非常详细地理解所有这些发现。我们的结果表明，集成的砷化铟/磷化铟量子点为砷化铟纳米线中的电子隧穿光谱提供了一个有前景的平台，它可以很容易地与各种超导材料接触，以研究近邻纳米线区域中的亚能隙态，或者用于表征量子 regime 中的热电纳米级器件。
