Fine-grained nanocrystalline silicon p-layer for high open circuit voltage a-Si:H solar cells

Hydrogenated amorphous silicon (a-Si:H) single-junction solar cells with high open circuit voltage (V_oc) are fabricated using a wide bandgap boron doped Si:H p-layer deposited at high hydrogen dilution, low substrate temperature and with H₂-plasma treatment that promotes nanocrystalline silicon (nc-Si:H) formation. This paper presents the structure of this p-type material characterized by Raman scattering spectroscopy and high resolution transmission electron microscope (HRTEM). It is found that the p-layer that leads to high V_oc a-Si:H solar cells is a mixed-phase material that contains fine-grained nc-Si:H embedded in a-Si:H matrix.