Study of Gold-Free Fully Cu-Metallized III-V Solar Cell

• Main Authors: Hsu, Ching-Hsiang, 許青翔
• Other Authors: Chang, Edward, Yi
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/75jgf6

博士 === 國立交通大學 === 照明與能源光電博士學位學程 === 104 === Solar cell is one of the fastest growing industries in the renewable energy field, since the solar energy could be converted into electricity directly by photovoltaic technology without the environmental pollution and the solar power will not be exhausted in the near future. In this study, copper based contacts to GaAs and Ge along with copper interconnects were developed and applied to the III-V solar cells to reduce the manufacture cost of the solar cell. Pd (15 nm)/Ge (150 nm) and Pt (5 nm)/Ti (50 nm)/Pt (60 nm) were used as the n-GaAs and p-Ge ohmic contact metals, the lowest values of specific contact resistance for the contacts were 4.4 x 10-6 Ω-cm2 and 6.9 x 10-6 Ω-cm2, respectively, after thermal annealing. The fully copper metallized InGaP/InGaAs/Ge triple-junctions solar cell shows conversion efficiency of about 23.11% and 82.48%, respectively, at AM1.5，25 oC. When the concentration ratio is further increased to 122X, the conversion efficiency and fill factor become about 37.21% and 83.98%, respectively, using these material systems. The solar cells with the proposed Cu-based structures were also subjected to high-temperature annealing (250 °C) and a high DC current (6.5 x 10-4 mA/µm2) stress test in this thesis. Overall, the solar cell adopting these Cu based contacts remained quite stable and demonstrated excellent performances after these reliability tests.