Counting What Can Be Counted: Evaluating the Limits of LEEM-EDX

This thesis evaluates the capabilities and detection limits of the energy- dispersive X-ray spectroscopy (EDX) system integrated into the ESCHER low-energy electron microscope (LEEM) for compositional analysis of in- situ grown thin-film Cs3Sb photocathodes. The project aimed to assess whether the photocathodes grown in the system exhibit stoichiometries consistent with expectations and to determine whether the LEEM-EDX setup can reliably measure them. Two complementary analysis methods, matrix-corrected least-squares (MLLSQ) fitting with standard-based quan- tification and Monte Carlo simulations of X-ray generation, were both im- plemented in DTSA-II and applied to photocathodes of varying thickness. The results show that typical thin-film photocathodes are near the de- tection limit of the system, making reliable quantification difficult, while thicker samples yield more distinct compositional information and more representative ratios. Although the findings indicate the...Show moreThis thesis evaluates the capabilities and detection limits of the energy- dispersive X-ray spectroscopy (EDX) system integrated into the ESCHER low-energy electron microscope (LEEM) for compositional analysis of in- situ grown thin-film Cs3Sb photocathodes. The project aimed to assess whether the photocathodes grown in the system exhibit stoichiometries consistent with expectations and to determine whether the LEEM-EDX setup can reliably measure them. Two complementary analysis methods, matrix-corrected least-squares (MLLSQ) fitting with standard-based quan- tification and Monte Carlo simulations of X-ray generation, were both im- plemented in DTSA-II and applied to photocathodes of varying thickness. The results show that typical thin-film photocathodes are near the de- tection limit of the system, making reliable quantification difficult, while thicker samples yield more distinct compositional information and more representative ratios. Although the findings indicate the photocathodes are approximately within the expected stoichiometric range, the current limitations of the setup prevent definite conclusions.Show less

Leiden University Student Repository

Documents

In Collections

Counting What Can Be Counted: Evaluating the Limits of LEEM-EDX