Lifetimes in aluminum-doped silicon

The carrier lifetimes in screen-printed Al-p⁺ regions are shown to be 3 orders of magnitude larger than the values expected from the extrapolation of the lifetime data measured on Al-doped Czochralski-grown silicon wafers. Device simulations show that the lifetime of 130 ns measured in Al-p⁺ regions enable open-circuit voltages of 670 mV and efficiencies of 21% on n-type silicon wafers. These results prove that the efficiency potential of screen-printed Al-p⁺ emitters for the application to rear-junction n-type cells is much higher than traditionally assumed.