Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH, United Kingdom.
Nano Lett. 2013 Mar 13;13(3):861-5. doi: 10.1021/nl303075q. Epub 2013 Feb 19.
The potential for scale-up coupled with minimized system size is likely to be a major determining factor in the realization of applicable quantum information systems. Nanofabrication technology utilizing the III-V semiconductor system provides a path to scalable quantum bit (qubit) integration and a materials platform with combined electronic/photonic functionality. Here, we address the key requirement of qubit-site and emission energy control for scale-up by demonstrating uniform arrays of III-V nanowires, where each nanowire contains a single quantum dot. Optical studies of single nanowire quantum dots reveal narrow linewidth exciton and biexciton emission and clear state-filling at higher powers. Individual nanowire quantum dots are shown to emit nonclassically with clear evidence of photon antibunching. A model is developed to explain unexpectedly large excited state separations as revealed by photoluminescence emission spectra. From measurements of more than 40 nanowire quantum dots, we find emission energies with an ensemble broadening of 15 meV. The combination of deterministic site control and the narrow distribution in ensemble emission energy results in a system readily capable of scaling for multiqubit quantum information applications.
规模化的潜力与最小化的系统规模相结合，很可能是实现适用的量子信息系统的一个主要决定因素。利用 III-V 半导体系统的纳米制造技术为可扩展的量子位（qubit）集成提供了一条途径，并且为具有电子/光子功能组合的材料平台提供了一条途径。在这里，我们通过演示包含单个量子点的 III-V 纳米线的均匀阵列来解决规模化的关键要求，即量子位位置和发射能的控制。对单个纳米线量子点的光学研究揭示了窄线宽激子和双激子发射，以及在更高功率下的清晰态填充。单个纳米线量子点被证明具有非经典发射，并清楚地显示出光子反聚束的证据。已经开发出一种模型来解释光致发光发射光谱所揭示的出乎意料的大激发态分离。从对 40 多个纳米线量子点的测量中，我们发现发射能量的集合展宽为 15 meV。确定性位置控制与集合发射能量分布的窄度相结合，使得该系统很容易适用于多量子比特量子信息应用。
