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 nitrogen onto the Cu{110} surface followed by annealing. We have examined these structures for a variety of nitrogen doses, beam energies, and annealing temperatures. Increasing the nitrogen dose resulted in the gradual appearance of an additional N-induced structure also possessing a (2 X 3) periodicity. Studies were performed on various desorption mechanisms (thermal and tip induced). Images of the surface after heating to temperatures at which partial desorption of the (2 X 3)N reconstruction 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 codomains of the (2 X 1)O and (2 X 3)N reconstructions. Images of the codomains yield the registry of features within the (2 X 3)N reconstructions with respect to the substrate and suggest a double added row mechanism for the formation of the (2 X 3)N reconstruction. Models are presented for both the (2 X 3)N-induced structures.