Investigation on current collection from a silicon quantum-dot p-i-n solar cell by varying dot size and insulating barrier layer thickness

In this article, the photo-current enhancement by inserting an active i-layer comprising bi-layers of silicon quantum dot/barrier in traditional pn-structure has been studied. The analysis of silicon quantum dot solar cell is based on the methodology adopted for InAs/GaAs quantum dot solar cell previously reported, with some assumptions and modifications. In this study, the experimental data for absorption coefficient and reflectance are used. The effect of various barrier layers on current collection such as SiO2 and SiC has been investigated by developing a realistic modeling on MATLAB platform. In this analysis, the effects of silicon quantum dot size, barrier layer thickness, number of bi-layers and silicon content have been analyzed. It has been observed that the enhancement in current in p-i-n-type cell by inserting an i-layer in pn-diode structure for SiO2 barrier layer is of the order of 1 mA/cm(2), whereas for SiC barrier layer it ranges from 6.5 to 17.4 mA/cm(2) for given dot size, silicon content and number of layers. The maximum achievable cell current of 30.28 mA/cm(2) has been observed with SiC barrier.