Bandgap engineering in III-V nanowires by post-growth hydrogen implantation

Quantum dots and rings in semiconductor nanowires are valuable assets in the toolbox for quantum optics applications. To create these structures, the electronic bandgap has to be engineered on the nanoscale, which is typically done by varying the material composition or crystal phase during growth. Even though this approach is very powerful, it gives limited control over the size and emission energy of the quantum structure. Here, we report bandgap engineering of GaAs/GaAsN nanowires by hydrogen implantation post-growth. The low concentration of N-atoms (0.7-3%) creates a perturbation potential leading to a downshift of the GaAs bandgap energy [1]. By forming stable N-H complexes, we can shift the bandgap by up to 400meV back to the value of GaAs in the regions subjected to low energy H irradiation. Simultaneously, we show that this H-implantation is accompanied by a giant optical signal increase of one order of magnitude due to a passivation of surface and interface states. With μ-Raman and μ-photoluminescence measurements we study the peculiarities of the material, while the preliminary g2-measurement demonstrates the potential of our nanowire material to act as single photon emitter.

[1] M. Yukimune, et al., Nanotech. 30, 244002 (2019)