An understanding of the interaction of organic molecules with semiconductors is important for both fundamental research and technological applications. With such knowledge, it may be possible to bond a wide range of useful organic molecules directly to the semiconductor surface. The adsorption of ethylene, C2H4, on the arsenic-terminated GaAs(100) surface has been studied using high-resolution electron energy-loss spectroscopy (HREELS). We find that ethylene molecules are chemisorbed on the surface in a near-sp(3) hybridisation state at 300 K. Conversion from the physisorption state at 100 K to the chemisorption state is observed when the sample temperature is raised to room temperature. The sticking coefficient for ethylene on the surface at 300 K is about two orders of magnitude lower than that at 100 K. The electron-stimulated desorption (ESD) with low-energy electrons (0-50 eV) of the physisorbed species leads to quite different behaviour than heating; specifically, the desorption of H+ and CH3+ ions is due to C-H and C=C bond scission. respectively. (C) 1999 Elsevier Science B.V. All rights reserved.
- electron energy loss spectroscopy
- electron stimulated desorption (ESD)
- III-V semiconductors
- surface molecules