Department of Physical Electronics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan.
Nanoscale Res Lett. 2013 Aug 23;8(1):361. doi: 10.1186/1556-276X-8-361.
To achieve a high-efficiency silicon nanowire (SiNW) solar cell, surface passivation technique is very important because a SiNW array has a large surface area. We successfully prepared by atomic layer deposition (ALD) high-quality aluminum oxide (Al2O3) film for passivation on the whole surface of the SiNW arrays. The minority carrier lifetime of the Al2O3-depositedSiNW arrays with bulk silicon substrate was improved to 27 μs at the optimum annealing condition. To remove the effect of bulk silicon, the effective diffusion length of minority carriers in the SiNW array was estimated by simple equations and a device simulator. As a result, it was revealed that the effective diffusion length in the SiNW arrays increased from 3.25 to 13.5 μm by depositing Al2O3 and post-annealing at 400°C. This improvement of the diffusion length is very important for application to solar cells, and Al2O3 deposited by ALD is a promising passivation material for a structure with high aspect ratio such as SiNW arrays.
为了实现高效的硅纳米线（SiNW）太阳能电池，表面钝化技术非常重要，因为 SiNW 阵列具有较大的表面积。我们成功地通过原子层沉积（ALD）在 SiNW 阵列的整个表面上制备了高质量的氧化铝（Al2O3）薄膜。在最佳退火条件下，沉积 Al2O3 的 SiNW 阵列的少数载流子寿命提高到 27 μs。为了去除体硅的影响，通过简单的方程和器件模拟器来估计 SiNW 阵列中少数载流子的有效扩散长度。结果表明，通过沉积 Al2O3 和在 400°C 下退火，SiNW 阵列中的有效扩散长度从 3.25 μm 增加到 13.5 μm。这种扩散长度的提高对于应用于太阳能电池非常重要，并且通过 ALD 沉积的 Al2O3 是具有高纵横比结构（如 SiNW 阵列）的有前途的钝化材料。
