Crystalline silicon photovoltaic cells used for power transmission from solar-pumped lasers: III. Prototype for proof of the light trapping concept

We have proven the light trapping concept for crystalline silicon (c-Si) photovoltaic (PV) cells used for power transmission from solar-pumped lasers (SPLs) emitting at 1064 nm. We fabricated a prototype of the PV cells in which four unique features were employed: (i) a 45-mu m-thick c-Si wafer and an aperture of 100 mu m diameter, (ii) a bandpass filter on the front surface and a diffuse reflector on the rear surface, (iii) a p(+)/p/n(+) configuration illuminated from the p(+)-layer, and (iv) an Al/Ag double-layered electrode on the p(+)-front layer and a Ag electrode on the n(+)-rear layer for compatibility of ohmic contacts and high reflectance. Under 1064 nm laser illumination at 4.8W/cm(2), the external quantum efficiency was as high as 0.92 despite the use of a thin c-Si wafer, resulting in a conversion efficiency of around 35%. No marked detrimental effect was observed under more intense illumination up to 21.3W/cm(2). (C) 2018 The Japan Society of Applied Physics.