Improving device efficiency for n-i-p type solar cells with various optimized active layers

We investigated n-i-p type single junction hydrogenated amorphous silicon oxide solar cells. These cells were without front surface texture or back reflector. Maximum power point efficiency of these cells showed that an optimized device structure is needed to get the best device output. This depends on the thickness and defect density (Nd) of the active layer. A typical 10% photovoltaic device conversion efficiency was obtained with a Nd = 8.86×1015 cm-3 defect density and 630 nm active layer thickness. Our investigation suggests a correlation between defect density and active layer thickness to device efficiency. We found that amorphous silicon solar cell efficiency can be improved to well above 10%.