Thin-Film InGaAs/GaAsP MQWs Solar Cell With Backside Nanoimprinted Pattern for Light Trapping

A light-trapping structure of the thin-film GaAs p-i-n single-junction solar cell with InGaAs/GaAsP multiple quantum wells (MQWs) was successfully demonstrated. Using a nanoimprinting method with ultraviolet curing resin, the submicron light-scattering dielectric array was fabricated on the back surface of the cell for enhanced optical absorption in the MQWs. The epitaxially grown photovoltaic active layer approximately 2.5 μm in thickness was successfully transferred to the stainless steel support substrate with backside light-scattering structure from the GaAs growth substrate. The light-trapping pattern-induced sample showed improved absorption in MQWs and resulted in 1.7 times larger quantum efficiency than the cell without the backside pattern.