AUGER-ELECTRON SPECTROSCOPIC ANALYSIS OF BARIUM FLUORIDE SURFACES EXPOSED TO SELENIUM VAPOR

(111)-oriented BaF2 substrates were exposed to selenium vapor in an atmospheric pressure hydrogen ambient at three temperatures: 592, 629 and 696-degrees-C. Auger electron spectroscopy analysis of exposed surfaces showed formation of BaSe patches, BaSe layers, and BaSe3/BaSe composite layers at these three temperatures, respectively. We speculate that BaSe reaction layers form epitaxially on BaF2 since cations in both materials have the same sublattice structure and the materials have a relatively small, 6 percent, lattice parameter mismatch. Such structure-preserving substrate surface reactions can occur during IV-VI semiconductor epitaxy on BaF2 and can play an important role in early stages of semiconductor growth.