Single-photon emitters are a prerequisite for many quantum technologies including quantum
communication and encryption. Until now, single photon emitters have mainly consisted of
quantum dots, single molecules, or localised defects in bulk structures. All of these approaches have
problems, either in integrating the single photon source in a device, or in the harvesting of the
photons after production.
Recently, single-photon emission has been observed from defects in single-layer hexagonal boron-
nitride (hBN), a wide-bandgap semiconductor. The defects introduce localized states inside the band
gap, and photons are generated by the electronic transitions between the localized states. As the
system is quasi two-dimensional, a probe can be placed arbitrarily close to the single photon source,
ensuring efficient harvesting, and since boron nitride is a bulk structure, integration into devices is
Through ion implantation techniques, it is possible to introduce many different species of atom into
the pristine boron nitride lattice, as either substitutional or interstitial vacancies, without disturbing
the global lattice structure. This project aims to simulate the behaviour of these point defects with the aim of identifying specific structures with promising properties for single photon emission.
The student will perform quantum mechanical computer simulations in the framework of density functional theory (DFT) to obtain the atomic structure and electronic energy levels of different point defects and impurity atoms in a single layer of hBN. Calculations will be performed using our in-house developed DFT code GPAW. From these calculations the characteristics of the photon emission spectrum will be derived and the most promising systems will be identified.
The project is well connected to ongoing research activities both within CAMD and at the Center for Nanostructured Graphene (CNG); you will thus be part of a larger team of researchers working on 2D materials and electronic structure theory. The data produced and results obtained in the course of the project will also be beneficial for the 2D Materials Database developed and maintained at CAMD.