Characterization of periodicity fluctuations in InGaN/GaN MQWs by the kinematical simulation of X-ray diffraction

X-ray diffraction patterns are widely used to calculate the periodicity fluctuation of multiple quantum wells (MQWs). Nonetheless, we find the commonly used formula sometimes cannot give an exact linear relationship between the full width at half maximum and the satellite peak orders. Here, based on the formula, we deduce a more accurate formula to characterize the periodicity fluctuations in InGaN/GaN MQWs. The revised formula has higher linearity correlation degree and the calculated interface roughness coincides well with X-ray reflectivity measurement results.