Phan Thanh Luan, Yu Woo Jong
Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
Sci Rep. 2020 Mar 2;10(1):3441. doi: 10.1038/s41598-020-60580-8.
We report a black silicon-carbon nanotube (bSi-CNT) hybrid structure for ultrahigh absorbance at wide spectral range of wavelength (300-1200 nm). CNTs are densely grown on entire bSi stems by chemical vapor deposition (CVD) through uniformly coating Fe catalyst. The bSi-CNT not only increases the surface roughness for enhancing the light suppression, but also allows the absorption of light in a wide wavelength range over the Si band gap (>1000 nm owing to 1.1 eV) due to the small band gap of CNT (0.6 eV). At short wavelength below Si band gap (<1000 nm), the absorbance of bSi-CNT shows average of 98.1%, while bSi shows 89.4%, which is because of high surface roughness of bSi-CNT that enhancing the light trapping. At long wavelength over Si band gap, the absorbance of bSi-CNT was maintained to 96.3% because of the absorption in CNT, while absorbance of bSi abruptly reduces with increase wavelength. Especially, the absorbance of bSi-CNT was showed 93.5% at 1200 nm, which is about 30~90% higher than previously reported bSi. Simple growth of CNTs on bSi can dramatically enhances the absorbance without using any antireflection coating layer. Thus, this study can be employed for realizing high efficiency photovoltaic, photocatalytic applications.
我们报道了一种黑色硅 - 碳纳米管（bSi - CNT）混合结构，其在宽波长光谱范围（300 - 1200 nm）内具有超高吸光度。通过均匀涂覆铁催化剂，利用化学气相沉积（CVD）法在整个bSi茎上密集生长碳纳米管。bSi - CNT不仅增加了表面粗糙度以增强光抑制，还由于碳纳米管的小带隙（0.6 eV）使得在硅带隙以上（由于1.1 eV，大于1000 nm）的宽波长范围内能够吸收光。在低于硅带隙的短波长（<1000 nm）下，bSi - CNT的吸光度平均为98.1%，而bSi为89.4%，这是因为bSi - CNT的高表面粗糙度增强了光捕获。在高于硅带隙的长波长下，由于碳纳米管的吸收，bSi - CNT的吸光度保持在96.3%，而bSi的吸光度随着波长增加而急剧降低。特别是，bSi - CNT在1200 nm处的吸光度为93.5%，比先前报道的bSi高约30% - 90%。在bSi上简单生长碳纳米管可以在不使用任何抗反射涂层的情况下显著提高吸光度。因此，本研究可用于实现高效光伏、光催化应用。
