A Zeiss Gemini 450 SEM was used to determine the morphology of the undoped and Sn-doped Shirley background subtraction, and core-level spectra were plotted to deconvolute spectra with contributions from multiple elements as necessary. A GL 30 asymmetric line shape was assumed for the core level emissions, with a ΔE of 9.34 eV for the Sb 3d doublet and a ΔE of 0.86 eV for the Se 3d.