SCANNING-TUNNELING-MICROSCOPY STUDIES OF (2X3)N-INDUCED STRUCTURES, THERMAL-DESORPTION, AND OXYGEN COADSORPTION ON THE CU(110) SURFACE

We have used scanning tunneling microscopy (STM) to investigate (2 X 3 )N-induced structures arising from the bombardment of activated nitrog en onto the Cu{110} surface followed by annealing. We have examined th ese structures for a variety of nitrogen doses, beam energies, and ann ealing temperatures. Increasing the nitrogen dose resulted in the grad ual appearance of an additional N-induced structure also possessing a (2 X 3) periodicity. Studies were performed on various desorption mech anisms (thermal and tip induced). Images of the surface after heating to temperatures at which partial desorption of the (2 X 3)N reconstruc tion occurred show that thermal desorption results in islands of clean Cu centered on step edges. Pulsing the voltage between the sample and tunneling tip was also found to induce desorption. We have formed cod omains of the (2 X 1)O and (2 X 3)N reconstructions. Images of the cod omains yield the registry of features within the (2 X 3)N reconstructi ons with respect to the substrate and suggest a double added row mecha nism for the formation of the (2 X 3)N reconstruction. Models are pres ented for both the (2 X 3)N-induced structures.