Showing papers by "Yang-Tse Cheng published in 1992"

Phase separation during co-deposition of Al-Ge thin films

Abstract: We present the results of a combined experimental and theoretical investigation of phase separation and microstructure development in co-deposited Al–Ge thin films. For small film thicknesses and deposition temperatures above 150 °C the phase-separated films consist of an array of domains of the Al- and Ge-rich terminal phases (lateral phase separation). Films deposited at 100 °C or less contained one or both of the terminal phases plus a metastable phase. We show that the domain structure evolves during deposition in a manner consistent with a surface interdiffusion controlled process. As film thickness increases we observe a transition from the laterally phase-separated microstructure to a layered microstructure exhibiting phase separation perpendicular to the film/substrate interface (transverse phase separation), with Al segregating to the film surface. We present a thermodynamic argument based on the competition between surface and interfacial free energies to explain this transition. Finally, we discuss the stability of the transverse phase-separated microstructure in the thick-film limit in terms of the transport of Ge through the Al-rich surface layer.

Method of forming silver/molybdenum surface coating material

Abstract: A method of forming friction-reducing and wear-resistant silver/molybdenum coating material by co-depositing quantities of silver and molybdenum simultaneously forming nano-crystalline binary mixtures on iron surfaces.

Epitaxial growth of double hexagonal close‐packed Nd on the α‐Fe (111) surface

Abstract: Epitaxial double hexagonal close‐packed (dhcp) Nd layers have been grown on the (111) surface of α‐Fe at 320 °C by electron beam evaporation in an ultrahigh vacuum environment. Conventional θ‐2θ diffraction and transmission electron microscopy show that the dhcp Nd films are oriented with the dhcp Nd (0001) plane parallel to the α‐Fe(111) plane and with the dhcp Nd [1120] direction parallel to the Fe[110] direction in the plane of the substrate. An epitaxial Fe/Nd/Fe trilayer structure with the same orientational relationships has also been made.

Structrual Characterization and Raman Scattering of Epitaxial Aluminum Nitride Thin Films on Si(111)

Abstract: Thin films of aluminum nitride were grown epitaxially on Si(111) by ultra-high-vacuum dc magnetron reactive sputter deposition. Epitaxy was achieved at substrate temperatures of 600°C or above. We report results of film characterization by x-ray diffraction, transmission electron microscopy, and Raman scattering.