Fabrication of CuI/a-Si:H/c-Si Structure for Application to Hole-selective Contacts of Heterojunction Si Solar Cells

We report on structural and optical properties of copper iodide (CuI) on crystalline Si (c-Si) and properties of the diode with intrinsic type (i-type) hydrogenated amorphous Si (aSi:H) at CuI/c-Si interface. The i-type a-Si:H layer was deposited on n-type c-Si by catalytic chemical vapor deposition (Cat-CVD) prior to deposition of CuI by spin-coating method. Higher rotational speed of 4000 rpm was found to be useful to suppress generation of large particles and absorption by CuI. The effective carrier lifetime was characterized for CuI/a-Si:H/c-Si/a-Si:H/CuI structures and it strongly depended on a-Si:H. The CuI/a-Si:H/c-Si diodes showed rectification behavior.