Huisheng Yang

Interface and Strain Energy Revolution Texture Map To Predict Structure and Optical Properties of Sputtered PbSe Thin Films

The preferred growth orientation of the sputtered lead selenide (PbSe) thin films on Si(100) substrates was thermodynamically simulated and calculated on the basis of the density functional theory. The results showed that the total free energy variation during the grain growth is dominated by the interface and strain energy minimization under certain conditions, indicating that the preferred growth orientation and related optical properties of the PbSe thin films can be effectively modified by these two energy variations. Thermodynamically, the PbSe[200] and PbSe[220] preferred orientations are obtained when the interface and strain energy minimization dominate the total free energy variation, respectively. A texture map related to the interface and strain energy revolution was obtained, which can be used to predict the structure and optical properties of the sputtered PbSe thin films, and its applicability was confirmed by the real X-ray diffraction and Fourier transform infrared spectroscopy experimental results of four midfrequency sputtered PbSe thin films with designed thickness and microstrain deposited on Si(100) substrates.

Adhesion of Sputtered Nickel Films on Polycarbonate Substrates

Nickel films were deposited by radio frequency magnetron sputtering on top of polycarbonate substrates. Surface energy of the substrate was measured by means of the contact angle technique. Effects of sputtering parameters on the critical load between the film and the substrate were determined by the universal mechanical testing system. Optimized fabrication parameters and their influence on the critical load between sputtered nickel films and polymer substrate were studied by means of the orthogonal experimental design. Increasing radio frequency power and time improved film critical load. The radio frequency power had a more pronounced effect on critical load than the sputter power. The plasma pretreatment with Ar gas modified the surface, leading to an increased surface energy, improving the chemical bonds between nickel and carbon atoms, and thereby enhanced the critical load. The adhesion mechanism is also discussed in this paper.

First principles calculations study of crystallographic orientation effects on SiC/Ti and SiC/Cr interfaces

Abstract First principles calculations of the SiC/Ti and SiC/Cr interfaces have been conducted based on the density functional theory, and adhesion properties along with the electronic structure were obtained. The crystallographic orientation dependence of the adhesion at the SiC/Ti and SiC/Cr interfaces has been investigated. The work of separation strongly depends on the crystallographic orientation with the SiC(11 2 ¯ 0)/Cr(001) interface having the highest value of Wsep = 4.71 J/m2. By analyzing the electronic structures, it was found that the charge transfer between C and Cr is larger, leading to stronger chemical bonds.