arXiv subjects

Akihiro Ohtake

Publications and source records attributed to Akihiro Ohtake.

3 recordsLinked to original sources

arXiv2002

As-rich GaAs(001) surfaces observed during As4-irradition by scanning tunneling microscopy

As-rich GaAs (001) surfaces are successfully observed during As4-irradition by a system in which scanning tunneling microscopy (STM) and molecular beam epitaxy can be performed simultaneously. With a substrate temperature of 440 C and an As4 partial pressure of 2x10-6 torr, reflection high energy electron diffraction patterns and reflectance anisotropy spectra confirm a c(4x4) As-stabilized surface. STM images clearly show alteration of the surface reconstructions while scanning. It is postulated that continual attachment / detachment of As molecules to and from the surface produces the observed dynamic behavior.

physics.chem-ph↗

arXiv2002

Structure analysis of the Ga-stabilized GaAs(001)-c(8x2) surface at high temperatures

Structure of the Ga-stabilized GaAs(001)-c(8x2) surface has been studied using rocking-curve analysis of reflection high-energy electron diffraction (RHEED). The c(8x2) structure emerges at temperatures higher than 600C, but is unstable with respect to the change to the (2x6)/(3x6) structure at lower temperatures. Our RHEED rocking-curve analysis at high temperatures revealed that the c(8x2) surface has the structure which is basically the same as that recently proposed by Kumpf et al. [Phys. Rev. Lett. 86, 3586 (2001)]. We found that the surface atomic configurations are locally fluctuated at high temperatures without disturbing the c(8x2) periodicity.

physics.chem-ph↗

arXiv2002

Ga-rich GaAs(001) surfaces observed during high-temperature annealing by scanning tunneling microscopy

Ga-rich GaAs (001) surfaces are successfully observed during high-temperature annealing by scanning tunneling microscopy (STM). With a substrate temperature of 550 C, reflection high-energy diffraction patterns and reflectance anisotropy spectra confirm a (4x2) Ga-stabilized surface. STM images clearly show alteration of the surface reconstructions while scanning. It is postulated that detaching and attaching of Ga adatoms may be the cause of these surface dynamics. For these conditions it is determined that zeta(4x4), zeta2(4x4) and zeta(4x6) reconstructions co-exist on the surface. The zeta2(4x4) reconstruction contains a Ga tetramer cluster and in more Ga-rich conditions, the zeta2(4x6) surface has a Ga octamer cluster.

physics.atm-clus↗