Ultrathin Gaas Solar Cells With A Nanostructured Back Mirror

We have designed and fabricated ultra-thin (t=120-220nm) GaAs solar cells. Multi-resonant light trapping is achieved with a nanostructured silver back mirror. The short-circuit current predicted by numerical calculations is Jsc=24.9mA/cm(2) for t=220nm. The nanostructured silver mirror is combined with localized ohmic contacts. Ultra-thin GaAs solar cells are patterned by soft nano-imprint lithography and transferred on a glass substrate. Short-circuit currents above 21mA/cm(2) have been measured on 220nm-thick solar cells.