Molybdenum oxide MoOx: A versatile hole contact for silicon solar cells

Abstract

This letter examines the application of transparent MoOx (x < 3) films deposited by thermal evaporation directly onto crystalline silicon (c-Si) to create hole-conducting contacts for silicon solar cells. The carrier-selectivity of MoOx based contacts on both n- and p-type surfaces is evaluated via simultaneous consideration of the contact recombination parameter J0c and the contact resistivity ρc. Contacts made to p-type wafers and p+ diffused regions achieve optimum ρc values of 1 and 0.2 mΩ·cm2, respectively, and both result in a J0c of ∼200 fA/cm2. These values suggest that significant gains can be made over conventional hole contacts to p-type material. Similar MoOx contacts made to n-type silicon result in higher J0c and ρc with optimum values of ∼300 fA/cm2 and 30 mΩ·cm2 but still offer significant advantages over conventional approaches in terms of contact passivation, optical properties, and device fabrication.