AlGaAs isn't only used as the passivation subcaste of CPV nanowires, reduces the recombination loss in the heavily unravel region and nonage carrier recombination at the top contact. The conversion effectiveness of GaAs nanowires can be greatly bettered by using AlGaAs rather of CPVin P member. This study achieved a maximum effectiveness enhancement of8.42. For axial nanowires, by using AlGaAs as the top P member, a fairly long top member can be used without reducing the device performance, which can promote the manufacturing and contact of nanowire array solar cells. For radial nanowires, AlGaAs/ GaAs nanowires show better forbearance to P- shell consistence and face conditions.
At low SRV, the increase of P- region length has no significant effect on the conversion effectiveness of AlGaAs/ GaAs NWs, although the overall immersion decreases with the increase of AlGaAs volume. More importantly, the longer AlGaAs region keeps utmost of the optic carriers down from the top contact, and smaller nonage carriers can be recombined at the contact. Still, for GaAs NWs, as the number of optic carriers generated in the top p region increases, the conversion effectiveness decreases linearly with the increase of the length of the p region. In the case of high SRV, the conversion effectiveness of AlGaAs/ GaAs NW indeed increases with the increase of P- region length, because the light generation in AlGaAs is concentrated in the center of NW and down from the face, performing in lower face recombination compared with GaAs region.
The performance of radial NW with different P shell consistence is also calculated.Fig. 5A shows the optic generation wind of AlGaAs/ GaAs radial NW. Analogous to that in axial NW, utmost optic carriers are generated in GaAs. The conversion effectiveness of AlGaAs/ GaAs and GaAs NW decreases with the increase of P shell consistence. At low SRV of 103 cm/ s, the effect of face recombination is nearly negligible; Thus, the drop of effectiveness substantially comes from the increase of the number of optic carriers generated in the P shell. Still, AlGaAs/ GaAs NW shows better forbearance to P- shell consistence because utmost optic generation can be limited to the internal GaAs region. As the SRV increases from 103 cm/ s to 107 cm/ s, the conversion effectiveness of AlGaAs/ GaAs NW decreases only slightly because the optic carriers are defended by the AlGaAs shell on the face. For NW with thicker AlGaAs shell, the declination of device performance is small because smaller carriers can reach and compound on the face. On the negative, high face recombination will seriously damage the performance of GaAs NW, especially in the case of thick P shell. Because for GaAs radial NW, the optic carriers generated in the P- shell can be fluently recombined on the face. When the P- shell consistence is 30 nm, the conversion effectiveness of GaAs NWS is only1.98, while the conversion effectiveness of AlGaAs/ GaAs NWS is10.4, which is8.42 advanced than that of GaAs NWs.