Temperature Dependence of Si-Based Thin-Film Solar Cells Fabricated on Amorphous to Microcrystalline Silicon Transition Phase

The temperature dependence of silicon (Si)-based thin-film single-junction solar cells, whose intrinsic absorbers were fabricated on the transition phase between hydrogenated amorphous silicon (a-Si:H) to hydrogenated microcrystalline silicon (µc-Si:H), was investigated. By varying the hydrogen dilution ratio, wide-band-gap protocrystalline silicon (pc-Si:H) and µc-Si:H absorber layers were obtained. Photo-current density–voltage (Photo-J–V) characteristics were measured under AM1.5 illumination at ambient temperatures in the range of 25–75 °C. We found that the solar cells with pc-Si:H, which exists just below the a-Si:H to µc-Si:H transition boundary, showed the lowest temperature coefficient (TC) for conversion efficiency (η) and open-circuit voltage (V_oc), while the solar cells fabricated at the onset of the a-Si:H to µc-Si:H phase transition exhibited a relatively high TC for η and V_oc. Experimental results indicated that pc-Si:H is a promising material for the absorber layer of the single junction or the top cell of tandem solar cells that operate in high temperature regions.