Reactive Ion Etching (RIE) and wet etching are employed in existing texturing processes to fabricate solar cells. Laser etching is used for particular purposes such as selective etching for grooves. However, such processes require a higher level of cost and longer processing time and those factors affect the unit cost of each process of fabricating solar cells. As a way to reduce the unit cost of this process of making solar cells, an atmospheric plasma source will be employed in this study for the texturing of crystalline silicon wafers. In this study, we produced the atmospheric plasma source and examined its basic properties. Then, using the prepared atmospheric plasma source, we performed the texturing process of crystalline silicon wafers. The results obtained from texturing processes employing the atmospheric plasma source and employing RIE were examined and compared with each other. The average reflectance of the specimens obtained from the atmospheric plasma texturing process was 7.88 %, while that of specimens obtained from the texturing process employing RIE was 8.04 %. Surface morphologies of textured wafers were examined and measured through Scanning Electron Microscopy (SEM) and similar shapes of reactive ion etched wafers were found. The Power Conversion Efficiencies (PCE) of the solar cells manufactured through each process were 16.97 % (atmospheric plasma texturing) and 16.29% (RIE texturing).

With the increase in installed solar energy capacity, comparison and analysis of the physical property values of solar cells are becoming increasingly important for production. Therefore, research on determining the physical characteristic values of solar cells is being actively pursued. In this study, a diode equation, which is commonly used to describe the I-V behavior and determine the electrical characteristic values of solar cells, was applied. Using this method, it is possible to determine the diode ideality factor (n) and series resistance (Rs) based on light I-V measurements. Thus, using a commercial screen-printed solar cell and an interdigitated back-contact solar cell, we determined the ideality factor (n) and series resistance (Rs) with a modified diode equation method for the light I-V curves. We also used the sun-shade method to determine the ideality factor (n) and series resistance (Rs) of the samples. The values determined using the two methods were similar. However, given the error in the sun-shade method, the diode equation is considered more useful than the sun-shade method for analyzing the electrical characteristics because it determines the ideality factor (n) and series resistance (Rs) based on the light I-V curves.

For rear metallization with Al paste, Al back contacts require good passivation, high reflectance, and a processing temperature window compatible with the front metal. In this paper, the effect of the firing ambient during the metallization process on the formation of Al rear metal was investigated. We chose three different gases as ambient gases during the firing process. Using SEM, we observed the formation of a back surface field in N2, O2, and Air ambients. To determine the effect of the ambient on Voc, the suns-Voc tool was used. In this study, we described the mechanism of burn-out of organic materials in Al paste during the firing process. The oxygen ambient plays an important role in the burn-out process. We calculated the efficiency with obtained the back surface recombination velocities using PC1D simulation. It was found that the presence of oxygen during the firing process influenced the uniform back surface field because the organic materials in the Al paste were efficiently burned out during heating. The optimized temperature with oxygen flow shows an absolute efficiency of 19.1% at PC1D simulation.

Solar cells exhibit different power outputs in different climates. In this study, the temperature dependence of open-circuit voltage(V-oc), short-circuit current(I-sc), fill factor(FF) and the efficiency of screen-printed single-crystal silicon solar cells were studied. One group was fabricated with homogeneously-doped emitters and another group was fabricated with selectively-doped emitters. While varying the temperature (25, 40, 60 and 80˚C), the current-voltage characteristics of the cells were measured and the leakage currents extracted from the current-voltage curve. As the temperature increased, both the homogeneously-doped and selectively-doped emitters showed a slight increase in I-sc and a rapid degradation of V-oc. The FF and efficiency also decreased as temperature increased in both groups. The temperature coefficient for each factor was calculated. From the current-voltage curve, we found that the main cause of V-oc degradation was an increase in the intrinsic carrier concentration. The temperature coefficients of the two groups were compared, leading to the idea that structural effects could also affect the temperature dependence of current-voltage characteristics.

To reduce manufacturing costs of crystalline silicon solar cells, silicon wafers have become thinner. In relation to this, the properties of the aluminium-back surface field (Al-BSF) are considered an important factor in solar cell performance. Generally, screen-printing and a rapid thermal process (RTP) are utilized together to form the Al-BSF. This study evaluates Al-BSF formation on a (111) textured back surface compared with a (100) flat back surface with variation of ramp up rates from 18 to 89˚C/s for the RTP annealing conditions. To make different back surface morphologies, one side texturing using a silicon nitride film and double side texturing were carried out. After aluminium screen-printing, Al-BSF formed according to the RTP annealing conditions. A metal etching process in hydrochloric acid solution was carried out to assess the quality of Al-BSF. Saturation currents were calculated by using quasi-steady-state photoconductance. The surface morphologies observed by scanning electron microscopy and a non-contacting optical profiler. Also, sheet resistances and bulk carrier concentration were measured by a 4-point probe and hall measurement system. From the results, a faster ramp up during Al-BSF formation yielded better quality than a slower ramp up process due to temperature uniformity of silicon and the aluminium surface. Also, in the Al-BSF formation process, the (111) textured back surface is significantly affected by the ramp up rates compared with the (100) flat back surface.