a-Si:H/c-Si interface hydrogenation for implied Voc = 755 mV in Silicon heterojunction solar cell

The amorphous (a-Si:H) and crystalline silicon (c-Si) interface plays a pivotal role in determining the V oc of the silicon heterojunction solar cell. Extrinsic hydrogenation by plasma treatment of the a-Si:H films is shown in this work to be a viable option to reduce the interface recombination. The mechanism of hydrogenation has been studied by analyzing the H bond configuration using Fourier Transform Infrared Spectroscopy and Raman spectroscopy. We have obtained an implied V oc of 755 mV and minority carrier lifetime of 4.6 ms for 10 nm thick hydrogen treated intrinsic a-Si:H films on textured n-type Cz silicon wafers. The proof of concept has been validated by fabricating front junction cells having V oc of 729 mV, with our best cell results reaching 20.2% efficiency.