Optical and electrical properties of nanostructured implanted silicon n+-p junction passivated by atomic layer deposited Al2O3

This paper investigates the optical and electrical properties of nanostructured implanted silicon junctions passivated by Al2O3 layers. A two-step ion implantation method has been developed to fabricate the nanostructured n+-p junctions with theoretical support of two dimensional Monte Carlo simulations to predict and optimize the junction profile. Dense and uniform arrays of silicon nanopillars and nanocones were formed by combining nanosphere lithography and dry etching, exhibiting a low reflectance in a broad spectrum from 300 to 800 nm. A conformal Al2O3 layer was deposited on the array by using thermal atomic layer deposition (ALD) to achieve chemical passivation effect. External quantum efficiency and power conversion efficiency of the junctions were measured versus nanostructuration and Al2O3 passivation. The results showed that significant enhancement of efficiency can be achieved on the passivated nanopillar-based junctions.