The energy resolution of ultraviolet photoelectron spectroscopy (UPS) analyzers is one of the important parameters for evaluating surface electronic structure. This study systematically explored the key factors that affect energy broadening, including the intrinsic broadening of the light source, the hot electron effect on the sample surface, and the resolution limit of the electron analyzer. By experimentally measuring the Fermi edge of the gold sample and using the nonlinear least squares fitting method of the convolution of the Fermi-Dirac distribution and the Gaussian function, we accurately evaluated the energy resolution of UPS. The results of this study provide a theoretical and experimental basis for further optimizing the energy resolution capability of photoelectron spectroscopy instruments.

photoelectron spectrum analyzer formatting,energy resolution,Nonlinear least squares method