Characterization of the protocrystalline silicon multilayer

The protocrystalline silicon (pc-Si:H) multilayer solar cell is very promising owing to its fast stabilization with low degradation against light irradiation. However, the pc-Si:H multilayers have not extensively been investigated in detail on its material characteristics yet. We present the material characteristics of pc-Si:H multilayers using a transmission electron microscopy (TEM), Fourier transform infra (FTIR) spectroscopy, Raman spectroscopy, constant photocurrent method (CPM) and quantum efficiency (QE) measurement. A TEM micrograph shows that a pc-Si:H multilayer has a repeatedly layered structure consisting of low hydrogen-diluted and highly hydrogen-diluted sublayers. FTIR spectra depict the strong vibration mode at 2090 cm−1 which is attributed to hydrogen-rich amorphous silicon (a-Si:H) regions of highly hydrogen-diluted sublayers. Based on these results, excellent light-soaking behavior of the pc-Si:H multilayers is primarily due to the repeatedly layered structure that improves a structural order in the material.