Sakr G, Sartel C, Sallet V, Lusson A, Patriarche G, Galtier P, Barjon J
GEMaC, Université de Versailles St Quentin en Yvelines, CNRS, Université Paris-Saclay, 45 avenue des Etats-Unis, 78035 Versailles Cedex, France.
J Phys Condens Matter. 2017 Dec 6;29(48):485706. doi: 10.1088/1361-648X/aa8a03.
The diffusion of excitons injected in ZnO/ZnMgO quantum well heterostructures grown by metal-organic-vapor-phase-epitaxy on non-polar ZnO substrates is investigated at room temperature. Cathodoluminescence linescans in a field-emission-gun scanning-electron-microscope are performed across cleaved cross-sections. A 55 nm diffusion length is assessed for excitons in bulk ZnMgO. When prepared as small angle bevels using focused ion beam (FIB), the effective diffusion length of excitons is shown to decrease down to 8 nm in the thinner part of the slab. This effect is attributed to non-radiative surface recombinations, with a 7 × 10 cm s recombination velocity estimated at the FIB-machined ZnMgO surface. The strong reduction of the diffusion extent in such thin lamellae usually used for transmission electron microscopy could be use improve the spatial resolution of cathodoluminescence images, often limited by diffusion processes.
