Analysis of P adsorption and desorption on the (001) InP surface using surface photoabsorption

We present an in situ study of P desorption and adsorption on the (001) InP surface using surface photoabsorption (SPA). The SPA spectra show three pe aks at 2.1, 2.9, and 3.1 eV. Here, based on previous studies, we have ident ified them as a P dimer related and two surface In dimer related peaks, res pectively. The initial sharp drop and the slow recovery of the SPA signal a t 430 nm after PH3 is switched on implies that at least two steps are invol ved in the P desorption process. We also observed a structure at 3.1 eV in the spectrum of the In-stabilized surface. We have determined from temperat ure dependent desorption measurements that the activation energy for P deso rption from this surface is 3.36 eV. (C) 1999 American Vacuum Society. [S07 34-2101(99)09105-8].