High-Efficiency Nanostructured Window GaAs Solar Cells

• Published in: Nano letters 2013-10, Vol.13 (10), p.4850-4856
• Main Authors: Liang, Dong, Kang, Yangsen, Huo, Yijie, Chen, Yusi, Cui, Yi, Harris, James S
• Format: Article
• Language: English
• Subjects: Applied sciences; Arsenicals - chemistry; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Contact; Electric Power Supplies; Electrical junctions; Electronics; Energy; Exact sciences and technology; Gallium - chemistry; Gallium arsenide; Gallium arsenides; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Molecular electronics, nanoelectronics; Nanostructure; Nanostructures - chemistry; Natural energy; Open circuit voltage; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Optics and Photonics; Particle Size; Photovoltaic cells; Photovoltaic conversion; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solar cells; Solar cells. Photoelectrochemical cells; Solar Energy; Sunlight; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl402680g

Nanostructures have been widely used in solar cells due to their extraordinary optical properties. In most nanostructured cells, high short circuit current has been obtained due to enhanced light absorption. However, most of them suffer from lowered open circuit voltage and fill factor. One of the main challenges is formation of good junction and electrical contact. In particular, nanostructures in GaAs only have shown unsatisfactory performances (below 5% in energy conversion efficiency) which cannot match their ideal material properties and the record photovoltaic performances in industry. Here we demonstrate a completely new design for nanostructured solar cells that combines nanostructured window layer, metal mesa bar contact with small area, high quality planar junction. In this way, we not only keep the advanced optical properties of nanostructures such as broadband and wide angle antireflection, but also minimize its negative impact on electrical properties. High light absorption, efficient carrier collection, leakage elimination, and good lateral conductance can be simultaneously obtained. A nanostructured window cell using GaAs junction and AlGaAs nanocone window demonstrates 17% energy conversion efficiency and 0.982 V high open circuit voltage.