Improved efficiency of InGaN/GaN-based multiple quantum well solar cells by reducing contact resistance

We report on the improvement in the performance of InGaN/GaN multi-quantum well-based solar cells by the introduction of a Cu-doped indium oxide (CIO) layer at the interface between indium tin oxide (ITO) p-electrode and p-GaN. The solar cell fabricated with the 3 nm-sample exhibits an external quantum efficiency of 29.8% (at a peak wavelength of 376 nm) higher than those (25.2%) of the cell with the ITO-only sample. The use of the 3-nm-thick CIO layer gives higher short circuit current density (0.72 mA/cm2) and fill factor (78.85%) as compared to those (0.65 mA/cm2 and 74.08%) of the ITO only sample. Measurements show that the conversion efficiency of the solar cells with the ITO-only sample and the 3 nm-sample is 1.12% and 1.30%, respectively. Based on their electrical and optical properties, the dependence of the CIO interlayer thickness on the efficiency of solar cells is discussed.

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► InGaN/GaN multi-quantum well-based solar cells with a Cu-doped indium oxide layer.
► Interlayered samples give slightly lower transmittance than ITO-only sample.
► The 3 nm-sample gives higher current density and fill factor than ITO only sample.
► The 3 nm-sample shows higher conversion efficiency than the ITO-only sample.