Epitaxy of intra-plane ordered (In,Ga)N monolayers towards single photon emission

• Applicant: Dr. Martin Albrecht
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 323347164

Single photon emitters hold the promise to serve as quantum bits in quantum communication, linear optical quantum computing and cryptography. Due to their thermal and chemical stability, their wide wavelength tunability from the visible to the ultraviolet spectral range (In,Ga,Al)N quantum dots are the most promising candidates for such devices. Despite the success in growing quantum dots, operating up to 300 K in 2014, the inherent piezoelectric fields, alloy fluctuations, size and shape control of the active zone pose severe challenges with respect to fast and efficient generation of a single photon flux at a well-defined wavelength. These issues severely decrease the potential of self-organized QDs for scalable systems since each QD is practically an individual structure. The scientific mission of this project is to tackle these issues by exploring (In,Ga)N monolayers as the active zone in site controlled nanowires for single photon emission. Depending of the growth conditions, (In,Ga)N monolayers can be grown with an ordered configuration of Indium and Gallium atoms within the layer. This strongly reduces spatial alloy composition fluctuations and thus the inhomogeneous broadening of the emission. The final goal of this project is to embed ordered (In,Ga)N monolayers in identically shaped nanowires by means of the top-down approach. This enables three-dimensional charge carrier confinement, permitting discrete energy levels for single photon emission. Due to the well-defined composition of the ordered (In,Ga)N monolayers and the uniform shape of the quantum wires, such quantum dots become uniform entities. These above-mentioned objectives will be achieved by means of a bilateral collaboration between the Leibniz-Institute for Crystal Growth (IKZ) and the Peking University (PKU) in China. We aim to unify a rich portfolio of competencies in the field of molecular beam epitaxy (MBE) with high-level structural analysis techniques carried out by means of transmission electron microscopy (TEM). Within this framework, both institutions will benefit from a mutual collaboration due to access to unique characterization methods and samples respectively, allowing them to expand the knowledge in their respective fields.

• DFG Programme: Research Grants
• International Connection: China
• Partner Organisation: Chinesisch-Deutsches Zentrum für Wissenschaftsförderung Beijing
• Co-Investigator: Professor Dr. Xinqiang Wang