No abstract

No abstract

The composition depth profiles of the Mn thin films grown on GaAs(00l) surface using MBE technique are studied with X-ray photoelectron spectroscopy(XPS) . The experimental results show that the fcc-Mn/GaAs(001) system grown on a 400 K substrate has a sandwich structure with a Mn-Ga-As buffer layer located between the fcc-Mn layer and the GaAs substrate; the α-Mn/GaAs (001) system grown on a 300 K substrate also has a similar buffer layer which is much thinner than that of the fcc-Mn/GaAs(001) system;and the system grown on a 450 K substrate is a Mn-Ga-As alloy beyond the GaAs substrate and it has no Mn-dominated area. It is concluded that to keep the substrate at a proper temperature(400 K) during growth to obtain a suitable thickness of buffer layer is an essential requirement to grow fcc-Mn on GaAs(00l) surface.

No abstract

Auger electron spectroscopy (AES), X-ray photoelectron spectroscop (XPS) and ultraviolet photoelectron spectroscopy (UPS) have been used to study the InSb(lll) surfaces treated with (NH4)O2Sx. It is found that after the sulfide treatment, the sample surfaces are covered by a thin overlayer of sulfide (8?), which prevents the sample surface from oxidization and carbon contamination in the air. XPS and UPS results show that S atoms bond to both Sb atoms and In atoms on the sample surfaces. Sb-S bonding peaks in the Sb3d spectra exhibit a core level shift of 1.9eV, the bonding of S to In atoms causes an In4d core level shift of 0.6-0.7eV. A thermal annealing at 350℃ gives rise to the decomposition of Sb-S bonding and the evaporation Sb atoms from the sample surfaces. In-S bonding can not be decomposed completely by annealing up to 500℃ and a small amount of S atoms remains on the sample surfaces in the form of indium sulfide.