NANO.IL.

Innovative Solar-cells Based on Light-funnels Arrays Realized on Thin Silicon-On-Insulator (SOI) Wafers

Sarah Sowmya Priya Konedana Department of Electrical & Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel

Internet-of-Things (IoT) is a system comprised of sensors that connects people, machines and the environment. A single typical IoT sensor unit is composed of an active sensing component, memories, processors, and communication. Silicon on insulator (SOI) wafer technology can integrate various components on a single silicon chip. Importantly, more often the IoT sensors require a photovoltaic unit as connectivity to the electrical grid is not available. However, the active SOI layer is several micros thick and therefore light absorption and the subsequent generation of photocurrent are very poor. One way by which light absorption can be significantly increased is by decorating the surface of the photovoltaic cell with arrays of subwavelength structures. Surface structuring can be done with ordered or disordered tiling of subwavelength features (e.g., nanopillars, nanorods, nanocones, etc.) which enhances the broadband absorption of the solar radiation due to light trapping. Recently, we introduced broadband absorption enhancement with free-floating arrays composed of subwavelength light funnels (LF)1, where a LF is an inverted cone with respect to the incoming radiation. The optical coupling of LF arrays with an underlying substrates was also studied2. Here we numerically examine (finite-difference time-domain electromagnetic calculations) the broadband absorption of LF arrays realized on SOI wafers. We show that with a careful engineering of the LF bottom diameter a ~10% broadband absorption enhancement compared with that of an optimized NP array, is realized. Therefore, we believe that LF arrays could be utilized for the realization of optically efficient photovoltaic cell on SOI wafers.

References

  1. Shalev, G., Schmitt, S. W., Embrechts, H., Brönstrup, G. & Christiansen, S. Enhanced photovoltaics inspired by the fovea centralis. Sci. Rep.5, 8570 (2015).
  2. Prajapati, A., Nissay, Y., Gabay, T. & Shalev, G. Light Trapping with Silicon Light Funnel Arrays. Materials .11, 445 (2018).








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