Maximum a posteriori estimation for high-throughput peak fitting in X-ray photoelectron spectroscopy

We introduce a peak fitting method to estimate the model parameters and the number of peaks without using the conventional trial-and-error approach. The proposed method automatically removes excess peaks using maximum a posteriori estimation. The computation is performed efficiently by the spectrum-adapted expectation–conditional maximisation algorithm with deterministic annealing. We apply the proposed method to synthetic and experimental data from a tunnel field-effect transistor. The proposed method identified two peak components in the experimental data from a MoS2 sheet, which are interpreted to be the Mo 3d3/2 and Mo 3d5/2 peaks. No peaks were detected on the p+-WSe2 sheet and hexagonal boron nitride (h-BN) within the measured binding energy range.