The stoichiometry value x of WO x , or its oxidation state, is crucial for improving performances of the hole-selective contact heterojunction silicon solar cell. However, it is challenging to tune the films' oxidation state using the well-known evaporation method. In this study, a simulation was performed to analyze the effect of x on short-circuit current (J sc ) loss, attributed to the holeselective contact in the device. Compared to the thickness of WO x layer, x has a more important role in minimizing J sc loss. Based on the simulation, the WO x /c-Si heterojunction solar cells having hole-selective WO x contacts with tuned x to vary its oxidation state were fabricated using reactive magnetron sputtering. The relationships of the open-circuit voltage (V oc ) and J sc with respect to x were similar. The experimentally determined J sc increased from 34.7 to 36.6 mA cm −2 when x was increased from 2.72 to 2.77; this result is consistent with the simulation. Nevertheless, fill factor (FF) reduced with the increase of x, owing to the reduced conductivity of WO x . Both oxidation state and film conductivity must be as high as possible to simultaneously achieve high V oc , J sc , and FF. The lowest x yielded a solar cell efficiency of 13.3%.

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The nuclear reactor emits various kinds of nuclear radiations during operation. However, the main contributions to the radiation field in the reactor are given by neutrons and gamma rays. These radiation components are the principal concern of reactor shielding. In our study the neutron and gamma radiation dose rates at different depths in concrete bio-shield of the PWR were calculated based on spherical model for M-C simulation with using MCNP4C2. The simulation results were compared with  the results obtained from calculations based on S$_{8}$P$_{3}$ spherical approximation with using the ANISN code.