Solar cells made by laser-induced diffusion directly from phosphine gas

A new method for making p-n junctions based on immersion in a transparent dopant gas followed by irradiation with a pulsed laser is presented. An alexandrite laser was used, operating at 0.73 μm where photolysis of the dopant gas PH3 does not occur. Multiple pulses of 2.2–2.7 J/cm2 were used to make Si solar cells with total area efficiencies up to 8.6% without benefit of antireflection coatings.