Toward Efficient Radial Junction Silicon Nanowire-Based Solar Mini-Modules

In this work, laser scribing is used to obtain a monolithic series connection between adjacent silicon nanowire radial junction (SiNW RJ) solar cells on the same glass substrate. The SiNW RJ solar cells have been deposited in a low-temperature plasma-enhanced chemical vapor deposition (PECVD) reactor in a single pump-down process. The crystalline SiNWs have been grown by plasma-assisted vapor-liquid-solid method using tin (Sn) metal drops as a growth catalyst. A detailed study of the laser scribing step P2 is performed for better selective removal of the SiNW RJs. The laser scribed spots are characterized by scanning electron microscopy (SEM) and Raman spectroscopy mapping. In addition, a silver grid is optimized and inkjet printed on top of the mini-modules for better device performance. Based on that, a very good performance of the SiNW RJ mini-modules is achieved with an energy conversion efficiency over 4% and power generation in the active area of 10 cm2. This work presents a break-through in the modularization of the SiNW RJ solar cells and demonstrates the potential of the silicon nanowire devices for industrial applications as well as their compatibility with industrial fabrication processes.