Silicon quantum dot solar cell using top-down approach

Abstract

The current trend of research in the area of third-generation photovoltaics is to increase the efficiency of solar cell device adopting alternate and novel ways such as use of quantum dots to absorb maximum solar spectrum. A new and low-cost top-down approach to fabricate silicon quantum dot solar cell (QDSC) using spin coating of Si QDs embedded in flowable oxide is proposed. Si QDs with diameter smaller than 8 nm were synthesized using top-down approach by ultrasonication of freestanding porous silicon films obtained by anodization of Si. Systematic measurements of current density--voltage (J--V), capacitance--voltage (C--V) and external quantum efficiency (EQE) were carried out. The QDSC exhibits photovoltaic effect, hysteresis in C--V characteristics and improved EQE performance in short wavelength as compared with a reference c-Si cell with same structure, but without QD layer. The novelty and simplicity of the QDSC fabrication process make these results important.