Time-resolved measurement of surface band bending of cleaved GaAs(110) andInP(110) by high resolution XPS

GaAs(100) and InP(100) samples were cleaved in UHV to give (110) surface in order to investigate their energy band changes using high resolution x-ray photoelectron spectroscopy (XPS) measurement. It was revealed that the sur face band of a heavy doped n-GaAs(110) sample bent upward 0.4 eV and that o f a heavy doped p-GaAs(110) bent downward 0.3 eV to the midgap after cleava ge whereas the surface band of a heavy doped n-InP(110) sample bent upward 0.1 eV and that of a heavy doped p-InP(110) bent downward 0.65 eV to the mi dgap. As for the causes of band bending, we excluded the possibility of sur face charging, X-Ray radiation damage and the effect of residual gas in UHV during XPS measurement. The experimental results strongly suggest that the band bending process was caused by the surface lattice relaxation after cl eavage. (C) 2000 Elsevier Science B.V. All rights reserved.