Highly efficient microcrystalline silicon solar cells deposited from a pure SiH4 flow

A time-resolved optical emission spectroscopic study identified transient behavior of the excited SiH emission in a parallel plate SiH4/H2 plasma. The transient behavior could be prevented by filling the background gas with H2 prior to plasma ignition. Applying this condition, state-of-the-art microcryst. silicon (mc-Si:H) could be deposited irresp. of the applied H2 flow, ultimately demonstrated by a 9.5% efficient solar cell deposited from pure SiH4. The results are discussed in terms of SiH4 back diffusion, i.e., an initial diffusion flux of SiH4 from the reactor dead vol. back into the plasma. [on SciFinder (R)]