Showing papers by "Takafumi Yao published in 1990"
TL;DR: In this article, a good agreement was found between the observed temporal dependence of the reflection high-energy electron diffraction (RHEED) intensity variation of a specular spot and the calculated surface coverage during sublimation and adsorption processes in atomic layer epitaxy.
Abstract: A good agreement is found between the observed temporal dependence of the reflection high‐energy electron diffraction (RHEED) intensity variation of a specular spot and the calculated temporal dependence of surface coverage during sublimation and adsorption processes in atomic layer epitaxy. Here the surface coverage is calculated on the basis of a phenomenological model in which precursor states are taken into account. The RHEED oscillation behavior during molecular beam epitaxy (MBE) growth of Zn chalcogenides is investigated for various growth conditions. The RHEED intensity saturates at a certain level and the saturation level is closely correlated with the surface stoichiometry or the surface coverage. It is concluded that the RHEED intensity variation corresponds to the change in surface coverage during ALE and MBE growth. It is possible to characterize the surface stoichiometry during atomic layer epitaxy (ALE) and MBE growth by RHEED.
23 citations
TL;DR: In this article, the activation energy for Se sublimation is evaluated to be 0.6±0.04 eV, and the adsorption time of Zn is almost constant for lower temperatures, while it seems to decrease for higher temperatures due to the sub-limation of Se atoms from the surface.
6 citations
01 Mar 1990
TL;DR: In this paper, the effects of molecular beam flux and substrate temperature on the MBE growth rate of ZnSe are studied and it is found that, at relatively high substrate temperatures, the growth rate is influenced by the desorption and adsorption of Se and Zn atoms.
Abstract: The effects of molecular beam flux and substrate temperature on the MBE growth rate of ZnSe are studied. It is found that, at relatively high substrate temperatures, the growth rate is influenced by the desorption and adsorption of Se and Zn atoms. The reduction of growth rate results from Se atom desorption, Zn atom desorption, and both Zn and Se atoms desorption at flux rations, JZn/JSe>1, <1, and ≅1, respectively. The activation energy values are 1.2eV for the desorption of Zn atoms and 0.86eV for the desorption of Se atoms. Three MBE growth models were applied to explain the present results. A model considering the desorption of Zn and Se atoms from precursor states is proposed in this paper and it can best explain the relationship between the growth rate and the substrate temperature or the flux ratio.
3 citations