Improved photovoltaic properties of Si quantum dots/SiC multilayers-based heterojunction solar cells by reducing tunneling barrier thickness

Abstract

Si quantum dots (Si QDs)/SiC multilayers were fabricated by annealing hydrogenated amorphous Si/SiC stacked structures prepared in plasma enhanced chemical vapor deposition (PECVD) system. The microstructures were examined by transmission electron microscopy (TEM) and Raman spectroscopy, and results demonstrate the formation of Si QDs. Moreover, p-i-n devices containing Si QDs/SiC multilayers were fabricated, and their photovoltaic property was investigated. It was found that these devices show the good spectral response in a wide wavelength range (400–1200 nm). And it was also observed that by reducing the thickness of SiC layer from 4 to 2 nm, the external quantum efficiency was obviously enhanced and the short circuit current density (J_sc) was increased from 17.5 to 28.3 mA/cm², indicating the collection efficiency of photo-generated carriers was improved due to the reduced SiC barriers.

Keywords

Si quantum dots (Si QDs) / SiC multilayer / solar cells / transmission electron microscopy (TEM) / Raman spectroscopy

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Acknowledgements

This work was supported by the National Natural Science Foundation of China (Grant Nos. 61036001 and 11274155) and the National Major Scientific Research Program of China (No. 2013CB632101).

RIGHTS & PERMISSIONS

2014 Higher Education Press and Springer-Verlag Berlin Heidelberg