Fig. 1. Schematic diagrams of simulation structures. (a1)(a2) Conventional nanowire array (NWA); (b1)(b2) bottom-reflectivity-enhanced nanowire array (BRE-NWA)

Fig. 2. The trend of device performance with the thickness of i region. (a) Conversion efficiencies of the devices with different thicknesses of i region; (b) current density-voltage curve of the device when thickness of i region is 30 nm

Fig. 3. Optical properties of NWA and BRE-NWA. (a) Reflectance; (b) absorptance; (c) transmittance; (d) cross-sectional view of three-dimensional photocarrier distribution

Fig. 4. Comparison of current density-voltage curves between the devices with two different structures

Fig. 5. The trend of device performance with nanowire length. (a) Conversion efficiencies of the devices with different nanowire lengths; (b) current density-voltage curve of the device with bottom-reflectivity-enhanced structure when the nanowire length is 3 μm