Phosphine adsorption and the production of phosphide phases on Cu(0 0 1)

The adsorption and thermal decomposition of PH3 on a Cu(0 0 1) surface has been investigated by means of high-resolution helium atom scattering, Auger electron spectroscopy and temperature programmed desorption. Phosphine adsorption at Tx<160 K produces a molecular overlayer structure with short-range order. Annealing of the low-temperature structure results in decomposition of the adsorbed PH3, and desorption of hydrogen between Tx=250 K and Tx=320 K. Molecular phosphine was not seen to desorb. Phosphine deposition at room temperature or above produces well-ordered copper–phosphorus phases exhibiting either c(6×8) or c(6×6) diffraction patterns, depending upon the deposition conditions. Auger electron spectra indicate that these ordered phases contain approximately 1/3 ML or more of phosphorus. Possible atomic models for the overlayer structures are discussed.