✍ Scribed by Gianluca Coletti; Paula C. P. Bronsveld; Giso Hahn; Wilhelm Warta; Daniel Macdonald; Bruno Ceccaroli; Karsten Wambach; Nam Le Quang; Juan M. Fernandez
No coin nor oath required. For personal study only.
The impact of the transition metals iron, chromium, nickel, titanium and copper on solar‐cell performance is investigated. Each impurity is intentionally added to the silicon feedstock used to grow p‐type, directionally solidified, multicrystalline silicon ingots. A state‐of‐the‐art screen‐print solar‐cell process is applied to this material. Impurities like iron, chromium and titanium cause a reduction in the diffusion length. Nickel does not reduce the diffusion length significantly, but strongly affects the emitter recombination, reducing the solar‐cell performance significantly. Copper has the peculiarity of impacting both base‐bulk recombination as well as emitter recombination. Two models based on the Scheil distribution of impurities are derived to fit the degradation along the ingot. Solar‐cell performances are modelled as a function of base‐bulk recombination and emitter‐bulk recombination. The model fits the experimental data very well and is also successfully validated. Unexpectedly, the distribution of impurities along the ingot, due to segregation phenomena (Scheil distribution), leaves its finger‐print even at the end of the solar‐cell process. A measure of impurity impact is defined as the level of impurity that causes a degradation in cell performance of less than 2% up to 90% of the ingot height. The advantage of this impurity‐impact metric is that it comprises the different impurities’ physical characters in one single parameter, which is easy to compare.
📜 SIMILAR VOLUMES
Metal-insulator-silicon (MIS) solar cells with and without grain boundaries were fabricated using polycrystalline Czochralski silicon. Scanned laser spot methods were used to provide high resolution photocurrent and surface reflection images of these cells. Electrically active grain boundaries, reve
Over the past decade, a vast literature describing silicon metal-insulatorsemiconductor solar cells has built up. In this paper the concepts emerging from this work which are in the present authors' opinion the most useful are identified and suggestions are made as to how this structure can be used
A silicon thin-film technology could lead to less expensive modules by the use of less silicon material and by the implementation of monolithic module processes. A technology based on polycrystalline-silicon thin-films with a grain size between 1 m and 1 mm (pc-Si), seems particularly promising sinc
The metal-semiconductor solar cell offers a simple structure to determine the photovoltaic behaviour of novel semiconductors, such as thin films of hydrogenated amorphous silicon (a-Si:H). It is known that solar cells made from this semiconductor must contain a wide built-in field region to collect