Enhanced photovoltaic performance of nanowire array solar cells with multiple diameters

• Published in: Optics express Vol. 26; no. 26; pp. A974 - A983
• Main Authors: Yan, Xin, Gong, Lei, Ai, Lingmei, Wei, Wei, Zhang, Xia, Ren, Xiaomin
• Format: Journal Article
• Language: English
• Published: United States 24.12.2018
• ISSN: 1094-4087; 1094-4087
• DOI: 10.1364/OE.26.00A974

A multi-diameter p-i-n junction GaAs nanowire (NW) array architecture is proposed for high-performance solar cells. Coupled three-dimensional optoelectronic simulations are performed to investigate the photovoltaic properties. The NW diameters are randomly selected within the range of 220-400 nm, following the Gaussian distribution. The results show that the absorption strongly depends on the diameter, and the multi-diameter NW array exhibits higher optical absorption, in comparison with the uniform-diameter counterpart. This is because of the superposition of multiple absorption peaks. Moreover, the multi-diameter NW array can efficiently enhance the effective absorption; that is, the depletion region absorption, which directly leads to increased photocurrent. A remarkable efficiency of 17% is obtained for a 16-diameter NW array solar cell with a full width at half maximum of the diameter distribution of 75 nm, higher than the best value (16.1%) of uniform-diameter device with an optimum diameter of 310 nm. This work demonstrates that the native diameter nonuniformity of self-organized nanowires is beneficial for high-performance photovoltaics with low cost and a simple fabrication process.