Measurement of Mg Content in Zn_1-xMg_xO Films by Electron Probe Microanalysis

Zn_1-xMg_xO films are grown on A-sapphire substrates by molecular beam epitaxy, and Mg content in the Zn_1-xMg_xO films is measured by electron probe microanalysis (EPMA) when the acceleration voltage, the emission current, and the magnification are set to be 1kV, 30μA and 1000, respectively. The dead time is controlled within 17%--20% during the easurement with the receive angle of characteristic x-ray of 45°. The Mg content of the ZnMgO film is calculated by the low energy calibration and the ZAF calibration. By comparing the measurement result with the theoretical analysis and the EPMA result with the inductively coupled plasma (ICP), one can obtain that the measured value of Mg content of the samples is in good agreement with the theoretical analysis no matter whether the phase separation exists or not, and the correctness of ICP and EPMA is valid when Mg content in the samples is less than 0.5.