HREELS studies of C₂H₄ adsorption on III-V semiconductor surfaces

The adsorption and decomposition of C₂H₄ on GaAs(100) and Al-GaAs(100) has been studied using TDS, AES and HREELS techniques. Ethene is adsorbed non-dissociatively between 150 and 650 K on both surfaces. On heating to 650 K approximately 60% of the adsorbed C₂H₄ is desorbed intact. The remainder is decomposed to CH₂ and CH species which remains at the surface for temperatures up to 800 K. Above 800 K dehydrogenation occurs to give the corresponding carbide. This results in significant contamination of the substrate surface. The effect is most significant on an Al-covered surface.