Abstract

Satellites in Earth’s orbit require a power source that can produce electrical energy for the duration of the orbit and can withstand the high radiation levels it is subjected to. Ultra-thin layers (less than 100 nm thick) of photovoltaic material possess an intrinsic tolerance to radiation [1], and could potentially be used on space craft without the need for a cover glass to protect the device from incoming radiation. This could offer flexibility of the device due to the absence of the cover glass and the small dimensions of the material. However, ultra-thin gallium arsenide (GaAs) photovoltaic cells absorbs less than 10% of incident photons during the first pass [1]. As such, a form of light management could be utilised to increase the number of photons absorbed by the material, and thus produce highly efficient ultra-thin photovoltaic cells [2].

This talk presents a light management structure produced from the relatively inexpensive material silicon using a polystyrene nanosphere mask and a modified Bosch etching process. Structures produced by both a single layer (SL) and double layer (DL) of nanospheres were simulated in a photovoltaic device. A silicon layer of thickness 100nm with a mask of a SL of nanospheres resulted in an improvement in absorption of the incident light of 72.4%, producing 12.4mA/cm2 compared to 9.79mA/cm2 without light management.

[1] L. Hirst, M. Yakes, J. Warner, M. Bennett, K. Schmieder, R. Walters, and P. Jenkins, “Intrinsic Radiation Tolerance of Ultra-Thin GaAs Solar Cells,” Applied Physics Letters, vol. 109, no. 3, p. 033908, 2016.

[2] Z. Yu, A. Raman, and S. Fan, “Nanophotonic Light-Trapping Theory for Solar Cells,” Applied Physics A, vol. 105, no. 2, pp. 329–339, 2011.