In this article, ultra-thin Al, Ag, Cu thin films with thickness d ~10nm are prepared by thermal evaporation, Ellipsometer
and Spectrophotometer are used to measure Ψ, ∆, R and T of samples. Based on the characteristics of different metal
materials, we choose proper physical model to analysis the dielectric function. Experimental results show that the
method of Ellipsometer with transmittance data fitting can describe optical constants of ultra-thin metal films, and all the
parameters of Ψ, ∆ and T show a good fitting result. Moreover, the reflection of samples simulated by MathCAD
software using Fresnel coefficient equations also follows the measured reflectance data.
Mo metal back contacts for CIGS solar cells have been reviewed. The electrical resistivity, reflectance and adhesive properties of Mo thin films are affected strongly by the film deposition parameters. A Mo thin film with low resistivity and good adhesion can be obtained through two-step process. This bilayer Mo thin film can be formed through the different film structures depending on the working pressure. A MoSe2 layer formed at CIGS/Mo interface changes the CIGS/Mo hetero-contact from Schottky-type contact to ohmic-type contact. It also improves the adhesion between CIGS and Mo layers when its c-axis is parallel to the Mo surface. Additionally, it forms the back surface field for CIGS solar cells. However, the MoSe2 formation and c-axis orientation depend on the state of Mo prior to selenization, the medium of selenization, and the substrate temperature during selenization. At last, a single layer Mo thin film with low enough resistivity and good adhesion has been fabricated successfully by the pulse magnetron sputtering technology with appropriate deposition parameters.
In this paper, Zinc Sulfide (ZnS) single-layer films were deposited on Germanium (Ge) substrate by thermal evaporation
with film thickness about 1600 nm, and deposition temperature were 115°C, 155°C and 230°C. Reflective index of Ge
substrate and ZnS film were measured by infrared spectroscopy and Spectroscopic Ellipsometry (SE). Additionally,
Scanning Electron Microscopy (SEM) was used to observe the thin film structure graphics. The experiment results
indicate that the prepared conditions have a great influence on optical constants of film, appropriately increase the
deposition temperature will be helpful for increasing the packing density, and the refractive index is closely related to the
surface micro-structure of film.