TY - JFULL AU - Chun-Yuan Huang and Chiao-Yang Cheng and Chun-Yem Huang and Yan-Kuin Su and James Chin-Lung Fang PY - 2011/8/ TI - Efficiency Improvements of GaAs-based Solar Cells by Hydrothermally-deposited ZnO Nanostructure Array T2 - International Journal of Materials and Metallurgical Engineering SP - 656 EP - 661 VL - 5 SN - 1307-6892 UR - https://publications.waset.org/pdf/9135 PU - World Academy of Science, Engineering and Technology NX - Open Science Index 55, 2011 N2 - ZnO nanostructures including nanowires, nanorods, and nanoneedles were successfully deposited on GaAs substrates, respectively, by simple two-step chemical method for the first time. A ZnO seed layer was firstly pre-coated on the O2-plasma treated substrate by sol-gel process, followed by the nucleation of ZnO nanostructures through hydrothermal synthesis. Nanostructures with different average diameter (15-250 nm), length (0.9-1.8 μm), density (0.9-16×109 cm-2) were obtained via adjusting the growth time and concentration of precursors. From the reflectivity spectra, we concluded ordered and taper nanostructures were preferential for photovoltaic applications. ZnO nanoneedles with an average diameter of 106 nm, a moderate length of 2.4 μm, and the density of 7.2×109 cm-2 could be synthesized in the concentration of 0.04 M for 18 h. Integrated with the nanoneedle array, the power conversion efficiency of single junction solar cell was increased from 7.3 to 12.2%, corresponding to a 67% improvement. ER -