Papers by Keyword: Photoemission

Abstract: Purified cadmium sulfide crystals were successfully synthesized from 1:2 molar ratio of Cd and S powders by a 900 W microwave plasma for 120 min and 140 min. In the present research, XRD and SAED patterns including SEM, TEM, and FIB images were used to indicate phase and morphology of the products, with their Raman peaks at 303 and 605 cm^-1. Photoemission was determined to be 537 nm, and direct energy gap (E_g) to be 2.48-2.51 eV.

Abstract: In situ monitoring of surface processes and understanding of growth processes are important in achieving precise control of crystal growth. Therefore, many surface monitoring techniques are used during crystal growth by molecular beam epitaxy (MBE). The most popular is reflection high-energy electron diffraction (RHEED) and photoemission current which provides information on the morphology during the growing surface. The photoemission oscillation technique has been successfully used in situ to monitor the growth of materials and to control the thickness as well as the roughness of the deposited layer. In this paper, we report results of atomic scale simulations used to study the dynamics of homoepitaxial growth of GaAs(001) β2(2x4) reconstructed surface and, in particular, the RHEED oscillations of the photoemission current.

Abstract: The atomic and electronic structure of 4H-SiC(1 1 02) surfaces were investigated using scanning tunneling microscopy (STM), low-energy electron diffraction (LEED) and photoemission (PES). Two well ordered phases existing on this surface, i.e. (2×1) and c(2×2) are discussed. The (2×1) phase consists of a Si adlayer which is topped by an array of ordered Si-nanowires with electronic states confined to one dimension. For the c(2×2) phase STM indicates the presence of adatoms and PES a surface composition close to bulk SiC stoichiometry. A detailed atomic model for this c(2×2) phase is proposed.