Abstract
For lower reflectance, we applied a maskless plasma texturing technique using reactive ion etching (RIE) on acidic-textured multicrystalline silicon (mc-Si) wafer. RIE texturing had a deep and narrow textured surface and showed excellent low reflectance. Due to plasma-induced damage, unless the RIE-textured surfaces have the proper damage removal etching (DRE), they have a drop inVocand FF. RIE texturing with a proper DRE had sufficiently higher short circuit current(Isc)than acidic-textured samples without a drop in open circuit voltage(Voc). And in order to improve efficiency of mc-Si solar cell, we applied RIE texturing with optimized DRE condition to selective emitter structure. In comparison with the acidic-textured solar cells, RIE-textured solar cells have above 200 mA absolute gain in Isc. And optimized RIE samples with a DRE by HNO3/HF mixture showed 17.6% conversion efficiency, which were made using an industrial screen printing process with selective emitter structure.
Highlights
In order to improve the solar cell performance, incoming light in the cell has to be coupled into the cell and transformed into electrical energy more effectively
The aim of this work was to find damage removal etching (DRE) conditions that create a texture with a low reflectance and without a drop of Voc and FF, which obtains a maximum improvement for Isc and conversion efficiency
It is clear that the selective emitter solar cell with the reactive ion etching (RIE) texturing has the improved quantum efficiency compared to acidic texturing for wavelength below 600 nm
Summary
In order to improve the solar cell performance, incoming light in the cell has to be coupled into the cell and transformed into electrical energy more effectively. Losses due to reflection and transmission of the incident light have to be reduced to increase the solar cell efficiency. From the time plasma etching was applied in the semiconductor industry for patterning Si substrates, it is known that plasma etching, under certain conditions, causes a surface texture of a very high roughness [3]. It is known that a less rough form of this texture can be used for more effective light coupling into Si substrates [5, 6]. The reflectivity can be well controlled by RIE This way of texturing is ideal for very fragile substrates. Surface damage may be caused by RIE-texturing [8] and result in a high surface recombination velocity due to the enlarged surface. Because problem of RIE may be that the energetic ions can introduce damage in the Si material [9], so Carriers have a large chance of International Journal of Photoenergy
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