Optical second surface reflector (OSR) is widely used as thermal control coating on the surface of spacecraft. Besides its thermal physics property such as solar absorption and thermal emissivity, its electrical property such as surface resistivity is used to prevent surface charging. Under the influence of space radiation environment, the surface electrical performance of OSR secondary surface mirror will be degraded, which will threaten the on-orbit safety and reliability of spacecraft. Based on the principle of dose depth distribution equivalence and total exposure equivalence, the influence of the space electron, proton and ultraviolet radiation environments on the surface electrical properties of OSR are experimentally studied, and its performance is in situ test. It was found that the resistivity of OSR secondary surface decreased exponentially with the increase of ultraviolet exposure and irradiation of electrons and protons. This shows that the surface conductivity of the OSR secondary surface mirror in space radiation environment increases and it has a better ability to resist surface charging and discharging effects.
Theory of micro spectral transmittance measurement and its characteristics have been analyzed. Measurement procedures and data processing method have been introduced. Micro spectral transmittance of micro integrated filters has been measured using PerkinElmer Lambda 1050 spectrophotometer with the combination of a Schwarzschild optical system microscope accessory, and the measured quantitative analysis results have been obtained. The incidence focused light spot size is about 20*40 um<sup>2</sup>. At last, micro spectral transmittance results for micro integrated filters have been compared with the spectral transmittance for large size samples, which are fabricated under the same condition and measured at normal incidence. The focused incidence for micro spectral measurement will cause a wavelength shift towards the shorter and a deformation transmittance curve, but those changes are in agreement with their theoretical simulations.
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 MoSe<sub>2</sub> 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 MoSe<sub>2</sub> 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.