The effect of Au layer thickness (1, 2.5, 5, 7.5 and 10 nm) on the low-temperature crystallization of Ge thin films (30 nm) was examined. It is found that the best Ge crystallinity is achieved at an Au layer thickness of 2.5 nm. This finding will open up the possibility to reduce the amount of Au consumption in the low-temperature crystallization process of Ge thin films.

No abstract

Au layer thickness dependence (9–34 nm) of Ge crystallization in the metal-induced layer exchange process has been investigated. It has been found that Ge crystals are (111) oriented when the Au layer is as thin as 9 nm, whereas crystal grains are randomly oriented when the Au layer is as thick as 34 nm. The difference is discussed in terms of the difference in the position of nucleation sites of Ge crystals.

The influence of the original amorphous Ge (a-Ge) layer thickness on the crystallization behavior by Au-induced crystallization at low temperature (220 °C) is studied. Initially, the coverage of the crystalline Ge (c-Ge) layer increases as the a-Ge layer thickness increases. A further increase in a-Ge layer thickness, however, results in the decrease of the coverage and appearance of the second Ge layer on top of the first layer, which results in the increase of surface roughness. The bottom c-Ge layer has a better crystal quality compared to the top layer. The maximum coverage of ∼97% with only a small amount of second layer is obtained by annealing an a-Ge(46 nm)/Au(29 nm) bilayer and a Hall effect hole mobility of as high as ∼85 cm2/V s is achieved.

Elements-added diamond-like carbon films for biomedical applications were investigated. The aim of this work was to study the effects of the elemental contents (silicon and silicon-nitrogen) in a DLC film on its properties for biomedical applications. Pure DLC, Si-DLC, and Si-N-DLC films were prepared from C2H2, C2H2 : TMS, and C2H2 : TMS : N2 gaseous mixtures, deposited on an AISI 316L substrate using the plasma-based ion implantation (PBII) technique. The structure of films was analyzed using Raman spectroscopy. The chemical composition of films was measured using energy dispersive X-ray spectroscopy (EDS). The average surface roughness of films was measured by using a surface roughness tester. The hardness and elastic modulus of films were measured by using a nanoindentation hardness tester. The friction coefficient of films was determined using a ball-on-disk tribometer. The surface contact angle was measured by a contact angle measurement. The corrosion performance of each specimen was measured using potentiodynamic polarization. The biocompatibility property of films was conducted using the MTT assay cytotoxicity test. The results indicate that the Si-N-DLC film shows the best hardness and friction coefficient (34.05 GPa and 0.13, respectively) with a nitrogen content of 0.5 at.%N, while the Si-DLC film with silicon content of 14.2 at.%Si reports the best contact angle and corrosion potential (92.47  and 0.398 V, respectively). The Si-N-DLC film shows the highest cell viability percentage of 81.96%, which is lower than the uncoated AISI 316L; this is a considerable improvement. All specimens do not demonstrate any cytotoxicity with approximate viabilities between 74% and 107%, indicating good biocompatibilities.