Adsorption and decomposition of t-butylphosphine (TBP) on an InP(0 0 1)-(2 x 4)/c(2 x 8) surface have been studied by scanning tunneling microscopy (STM), temperature programmed desorption (TPD), and high-resolution electron energy loss spectroscopy (HREELS). It is found that TBP is adsorbed at the edge of the dimer rows (about 60%), in the missing dimer rows (about 30%), and at the center of the dimer rows (about 10%) at RT. The TPD result indicates that t-butyl radical and isobutylene are evolved from the TBP-adsorbed InP(0 0 1) surface. HREELS spectra suggest that TBP is partially dissociated on the surface at 300 K and that most of TBP is evolved up to 600 K through decomposition. The decomposition mechanism for TBP on the surface is discussed. (C) 2003 Elsevier Science B.V. All rights reserved.