Nondestructive atomic compositional analysis of BeMgZnO quaternary alloys using ion beam analytical techniques

•BeMgZnO thin layers were grown with plasma-assisted molecular beam epitaxy (MBE).•The Be contents were accurately measured with RBS and proton elastic backscattering.•The Tauc bandgap was measured from optical transmittance experiments.•The bandgap has been varied between 3.26eV and 4.62eV via the Be and Mg content.•Experimental and density functional theory calculated bandgaps were in good agreement. The atomic composition with less than 1–2atom% uncertainty was measured in ternary BeZnO and quaternary BeMgZnO alloys using a combination of nondestructive Rutherford backscattering spectrometry with 1MeV He+ analyzing ion beam and non-Rutherford elastic backscattering experiments with 2.53MeV energy protons. An enhancement factor of 60 in the cross-section of Be for protons has been achieved to monitor Be atomic concentrations. Usually the quantitative analysis of BeZnO and BeMgZnO systems is challenging due to difficulties with appropriate experimental tools for the detection of the light Be element with satisfactory accuracy. As it is shown, our applied ion beam technique, supported with the detailed simulation of ion stopping, backscattering, and detection processes allows of quantitative depth profiling and compositional analysis of wurtzite BeZnO/ZnO/sapphire and BeMgZnO/ZnO/sapphire layer structures with low uncertainty for both Be and Mg. In addition, the excitonic bandgaps of the layers were deduced from optical transmittance measurements. To augment the measured compositions and bandgaps of BeO and MgO co-alloyed ZnO layers, hybrid density functional bandgap calculations were performed with varying the Be and Mg contents. The theoretical vs. experimental bandgaps show linear correlation in the entire bandgap range studied from 3.26eV to 4.62eV. The analytical method employed should help facilitate bandgap engineering for potential applications, such as solar blind UV photodetectors and heterostructures for UV emitters and intersubband devices.