Adsorption and decomposition of triethylindium on an InP(0 0 1)-(2×4) surface studied by STM, TPD, and HREELS

Adsorption and decomposition of triethylindium (TEI) on an InP(0 0 1)-(2×4) surface have been studied by scanning tunneling microscopy (STM), temperature programmed desorption (TPD), and high-resolution electron energy loss spectroscopy (HREELS). Filled-state STM images indicate that TEI molecules are preferentially adsorbed at the center of the hetero(mixed-)-dimer rows along the [1 1̄ 0] direction. A line profile of empty-state STM images concludes that TEI is adsorbed on the P atom at the surface. TPD data and HREELS spectra show that ethyl radical and ethylene are evolved at about 380 and 435 K, respectively, as decomposition products. The HREELS spectra suggest that TEI is adsorbed molecularly at RT and that vibration modes related to hydrocarbon disappeared at about 500 K. Adsorption sites and the decomposition mechanism are discussed in terms of the (2×4) surface structure.