Fabrication of Active Microfluidics on Glass with Semiconductor Grade Material

status: publishe

Passivating electron-selective contacts for silicon solar cells based on an a-Si: H/TiOx stack and a low work function metal

In this work, the ATOM (intrinsic a-Si:H/TiOx/low work function metal) structure is investigated to realize high-performance passivating electron-selective contacts for crystalline silicon solar cells. The absence of a highly doped Si region in this contact structure is meant to reduce the optoelectrical losses. We show that a low contact resistivity (ρc) can be obtained by the combined effect of a low work function metal, such as calcium (Φ 2.9 eV), and Fermi-level depinning in the metal-insulator-semiconductor contact structure (where in our case TiOx acts as the insulator on the intrinsic a-Si:H passivating layer). TiOx grown by ALD is effective to achieve not only a low ρc but also good passivation properties. As an electron contact in silicon heterojunction solar cells, inserting interfacial TiOx at the i-a-Si:H/Ca interface significantly enhances the solar cell conversion efficiency. Consequently, the champion solar cell with the ATOM contact achieves a VOC of 711 mV, FF of 72.9%, JSC of 35.1 mA/cm2, and an efficiency of 18.2%. The achievement of a high VOC and reasonable FF without the need for a highly doped Si layer serves as a valuable proof of concept for future developments on passivating electron-selective contacts using this structure

Passivating electron-selective contacts for silicon solar cells based on an a-Si:H/TiOx stack and a low work function metal

Copyright © 2018 John Wiley & Sons, Ltd. In this work, the ATOM (intrinsic a-Si:H/TiO x /low work function metal) structure is investigated to realize high-performance passivating electron-selective contacts for crystalline silicon solar cells. The absence of a highly doped Si region in this contact structure is meant to reduce the optoelectrical losses. We show that a low contact resistivity (ρ c ) can be obtained by the combined effect of a low work function metal, such as calcium (Φ 2.9 eV), and Fermi-level depinning in the metal-insulator-semiconductor contact structure (where in our case TiO x acts as the insulator on the intrinsic a-Si:H passivating layer). TiO x grown by ALD is effective to achieve not only a low ρ c but also good passivation properties. As an electron contact in silicon heterojunction solar cells, inserting interfacial TiO x at the i-a-Si:H/Ca interface significantly enhances the solar cell conversion efficiency. Consequently, the champion solar cell with the ATOM contact achieves a V OC of 711 mV, FF of 72.9%, J SC of 35.1 mA/cm 2 , and an efficiency of 18.2%. The achievement of a high V OC and reasonable FF without the need for a highly doped Si layer serves as a valuable proof of concept for future developments on passivating electron-selective contacts using this structure.status: publishe

Passivating electron-selective contacts for silicon solar cells based on an a-Si:H/TiO\u3csub\u3ex\u3c/sub\u3e stack and a low work function metal

\u3cp\u3eIn this work, the ATOM (intrinsic a-Si:H/TiO\u3csub\u3ex\u3c/sub\u3e/low work function metal) structure is investigated to realize high-performance passivating electron-selective contacts for crystalline silicon solar cells. The absence of a highly doped Si region in this contact structure is meant to reduce the optoelectrical losses. We show that a low contact resistivity (ρ\u3csub\u3ec\u3c/sub\u3e) can be obtained by the combined effect of a low work function metal, such as calcium (Φ 2.9 eV), and Fermi-level depinning in the metal-insulator-semiconductor contact structure (where in our case TiO\u3csub\u3ex\u3c/sub\u3e acts as the insulator on the intrinsic a-Si:H passivating layer). TiO\u3csub\u3ex\u3c/sub\u3e grown by ALD is effective to achieve not only a low ρ\u3csub\u3ec\u3c/sub\u3e but also good passivation properties. As an electron contact in silicon heterojunction solar cells, inserting interfacial TiO\u3csub\u3ex\u3c/sub\u3e at the i-a-Si:H/Ca interface significantly enhances the solar cell conversion efficiency. Consequently, the champion solar cell with the ATOM contact achieves a V\u3csub\u3eOC\u3c/sub\u3e of 711 mV, FF of 72.9%, J\u3csub\u3eSC\u3c/sub\u3e of 35.1 mA/cm\u3csup\u3e2\u3c/sup\u3e, and an efficiency of 18.2%. The achievement of a high V\u3csub\u3eOC\u3c/sub\u3e and reasonable FF without the need for a highly doped Si layer serves as a valuable proof of concept for future developments on passivating electron-selective contacts using this structure.\u3c/p\u3

Silicon Heterojunction Cells with Improved Spectral Response Using n-type mu c-Si from a Novel PECVD Approach

One of the promising ways to increase the efficiency of silicon heterojunction (SHJ) cells is to replace the doped hydrogenated amorphous silicon (a-Si:H) contact layer by doped hydrogenated microcrystalline silicon (mu c-Si:H) which has better suited opto-electrical properties. In this work, we report on the development of a plasma-enhanced chemical vapor deposition process for mu c-Si:H. We demonstrate an n-type mu c-Si:H layer with high crystalline fraction and low parasitic absorption. The developed layer is implemented as the front electron contact of a SHJ cell. A significant improvement in J(sc) of 0.9 mA/cm(2) is achieved on device level while maintaining high V-OC values (> 725 mV), leading to an efficiency of 20.6% for the best cell. Cell efficiency is limited by a decreased FF which is attributed to the increased sensitivity of mu c-Si:H layers to ITO sputtering damage.The authors gratefully acknowledge the financial support of imec's industrial affiliation program for Si-PV. Part of this project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 657270