High efficiency AZO-InP nanopillar-based heterojunction solar cells

•We produced high efficiency AZO-InP nanopillar solar cells.•The AZO layer is used not only as a transparent electrode, but also as a rectifying junction with InP.•The InP nanopillar array reduced light reflection dramatically.•The AZO-InP nanopillar solar cells exhibited the efficiency of 17.1%.

This paper reports heterojunction solar cells consisting of InP nanopillars and aluminum-doped zinc oxide (AZO). The AZO layer sputtered on an InP surface is used not only as a transparent electrode, but also as an excellent rectifying junction with InP. More importantly, the wide-bandgap-AZO functions as a window layer of solar cells, thereby suppressing carrier recombination loss at the AZO-InP heterointerface. The InP nanopillar array reduces the light reflectance and increases the optical path length of the solar cells. The AZO-InP nanopillar-based heterojunction solar cells exhibited an open-circuit voltage, short-circuit current density, fill-factor, and power-conversion efficiency of 0.68 V, 36.8 mA/cm2, 68%, and 17.1%, respectively, under air-mass 1.5 simulated solar illumination (100 mW/cm2).